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1da177e4 LT |
1 | /* |
2 | * linux/kernel/signal.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * | |
6 | * 1997-11-02 Modified for POSIX.1b signals by Richard Henderson | |
7 | * | |
8 | * 2003-06-02 Jim Houston - Concurrent Computer Corp. | |
9 | * Changes to use preallocated sigqueue structures | |
10 | * to allow signals to be sent reliably. | |
11 | */ | |
12 | ||
1da177e4 LT |
13 | #include <linux/slab.h> |
14 | #include <linux/module.h> | |
1da177e4 LT |
15 | #include <linux/init.h> |
16 | #include <linux/sched.h> | |
17 | #include <linux/fs.h> | |
18 | #include <linux/tty.h> | |
19 | #include <linux/binfmts.h> | |
20 | #include <linux/security.h> | |
21 | #include <linux/syscalls.h> | |
22 | #include <linux/ptrace.h> | |
7ed20e1a | 23 | #include <linux/signal.h> |
fba2afaa | 24 | #include <linux/signalfd.h> |
c59ede7b | 25 | #include <linux/capability.h> |
7dfb7103 | 26 | #include <linux/freezer.h> |
84d73786 SB |
27 | #include <linux/pid_namespace.h> |
28 | #include <linux/nsproxy.h> | |
29 | ||
1da177e4 LT |
30 | #include <asm/param.h> |
31 | #include <asm/uaccess.h> | |
32 | #include <asm/unistd.h> | |
33 | #include <asm/siginfo.h> | |
e1396065 | 34 | #include "audit.h" /* audit_signal_info() */ |
1da177e4 LT |
35 | |
36 | /* | |
37 | * SLAB caches for signal bits. | |
38 | */ | |
39 | ||
e18b890b | 40 | static struct kmem_cache *sigqueue_cachep; |
1da177e4 | 41 | |
1da177e4 LT |
42 | |
43 | static int sig_ignored(struct task_struct *t, int sig) | |
44 | { | |
45 | void __user * handler; | |
46 | ||
47 | /* | |
48 | * Tracers always want to know about signals.. | |
49 | */ | |
50 | if (t->ptrace & PT_PTRACED) | |
51 | return 0; | |
52 | ||
53 | /* | |
54 | * Blocked signals are never ignored, since the | |
55 | * signal handler may change by the time it is | |
56 | * unblocked. | |
57 | */ | |
325d22df | 58 | if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig)) |
1da177e4 LT |
59 | return 0; |
60 | ||
61 | /* Is it explicitly or implicitly ignored? */ | |
62 | handler = t->sighand->action[sig-1].sa.sa_handler; | |
63 | return handler == SIG_IGN || | |
64 | (handler == SIG_DFL && sig_kernel_ignore(sig)); | |
65 | } | |
66 | ||
67 | /* | |
68 | * Re-calculate pending state from the set of locally pending | |
69 | * signals, globally pending signals, and blocked signals. | |
70 | */ | |
71 | static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked) | |
72 | { | |
73 | unsigned long ready; | |
74 | long i; | |
75 | ||
76 | switch (_NSIG_WORDS) { | |
77 | default: | |
78 | for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;) | |
79 | ready |= signal->sig[i] &~ blocked->sig[i]; | |
80 | break; | |
81 | ||
82 | case 4: ready = signal->sig[3] &~ blocked->sig[3]; | |
83 | ready |= signal->sig[2] &~ blocked->sig[2]; | |
84 | ready |= signal->sig[1] &~ blocked->sig[1]; | |
85 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
86 | break; | |
87 | ||
88 | case 2: ready = signal->sig[1] &~ blocked->sig[1]; | |
89 | ready |= signal->sig[0] &~ blocked->sig[0]; | |
90 | break; | |
91 | ||
92 | case 1: ready = signal->sig[0] &~ blocked->sig[0]; | |
93 | } | |
94 | return ready != 0; | |
95 | } | |
96 | ||
97 | #define PENDING(p,b) has_pending_signals(&(p)->signal, (b)) | |
98 | ||
7bb44ade | 99 | static int recalc_sigpending_tsk(struct task_struct *t) |
1da177e4 LT |
100 | { |
101 | if (t->signal->group_stop_count > 0 || | |
102 | PENDING(&t->pending, &t->blocked) || | |
7bb44ade | 103 | PENDING(&t->signal->shared_pending, &t->blocked)) { |
1da177e4 | 104 | set_tsk_thread_flag(t, TIF_SIGPENDING); |
7bb44ade RM |
105 | return 1; |
106 | } | |
b74d0deb RM |
107 | /* |
108 | * We must never clear the flag in another thread, or in current | |
109 | * when it's possible the current syscall is returning -ERESTART*. | |
110 | * So we don't clear it here, and only callers who know they should do. | |
111 | */ | |
7bb44ade RM |
112 | return 0; |
113 | } | |
114 | ||
115 | /* | |
116 | * After recalculating TIF_SIGPENDING, we need to make sure the task wakes up. | |
117 | * This is superfluous when called on current, the wakeup is a harmless no-op. | |
118 | */ | |
119 | void recalc_sigpending_and_wake(struct task_struct *t) | |
120 | { | |
121 | if (recalc_sigpending_tsk(t)) | |
122 | signal_wake_up(t, 0); | |
1da177e4 LT |
123 | } |
124 | ||
125 | void recalc_sigpending(void) | |
126 | { | |
cc5f916e | 127 | if (!recalc_sigpending_tsk(current) && !freezing(current)) |
b74d0deb RM |
128 | clear_thread_flag(TIF_SIGPENDING); |
129 | ||
1da177e4 LT |
130 | } |
131 | ||
132 | /* Given the mask, find the first available signal that should be serviced. */ | |
133 | ||
fba2afaa | 134 | int next_signal(struct sigpending *pending, sigset_t *mask) |
1da177e4 LT |
135 | { |
136 | unsigned long i, *s, *m, x; | |
137 | int sig = 0; | |
138 | ||
139 | s = pending->signal.sig; | |
140 | m = mask->sig; | |
141 | switch (_NSIG_WORDS) { | |
142 | default: | |
143 | for (i = 0; i < _NSIG_WORDS; ++i, ++s, ++m) | |
144 | if ((x = *s &~ *m) != 0) { | |
145 | sig = ffz(~x) + i*_NSIG_BPW + 1; | |
146 | break; | |
147 | } | |
148 | break; | |
149 | ||
150 | case 2: if ((x = s[0] &~ m[0]) != 0) | |
151 | sig = 1; | |
152 | else if ((x = s[1] &~ m[1]) != 0) | |
153 | sig = _NSIG_BPW + 1; | |
154 | else | |
155 | break; | |
156 | sig += ffz(~x); | |
157 | break; | |
158 | ||
159 | case 1: if ((x = *s &~ *m) != 0) | |
160 | sig = ffz(~x) + 1; | |
161 | break; | |
162 | } | |
163 | ||
164 | return sig; | |
165 | } | |
166 | ||
dd0fc66f | 167 | static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags, |
1da177e4 LT |
168 | int override_rlimit) |
169 | { | |
170 | struct sigqueue *q = NULL; | |
10b1fbdb | 171 | struct user_struct *user; |
1da177e4 | 172 | |
10b1fbdb LT |
173 | /* |
174 | * In order to avoid problems with "switch_user()", we want to make | |
175 | * sure that the compiler doesn't re-load "t->user" | |
176 | */ | |
177 | user = t->user; | |
178 | barrier(); | |
179 | atomic_inc(&user->sigpending); | |
1da177e4 | 180 | if (override_rlimit || |
10b1fbdb | 181 | atomic_read(&user->sigpending) <= |
1da177e4 LT |
182 | t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur) |
183 | q = kmem_cache_alloc(sigqueue_cachep, flags); | |
184 | if (unlikely(q == NULL)) { | |
10b1fbdb | 185 | atomic_dec(&user->sigpending); |
1da177e4 LT |
186 | } else { |
187 | INIT_LIST_HEAD(&q->list); | |
188 | q->flags = 0; | |
10b1fbdb | 189 | q->user = get_uid(user); |
1da177e4 LT |
190 | } |
191 | return(q); | |
192 | } | |
193 | ||
514a01b8 | 194 | static void __sigqueue_free(struct sigqueue *q) |
1da177e4 LT |
195 | { |
196 | if (q->flags & SIGQUEUE_PREALLOC) | |
197 | return; | |
198 | atomic_dec(&q->user->sigpending); | |
199 | free_uid(q->user); | |
200 | kmem_cache_free(sigqueue_cachep, q); | |
201 | } | |
202 | ||
6a14c5c9 | 203 | void flush_sigqueue(struct sigpending *queue) |
1da177e4 LT |
204 | { |
205 | struct sigqueue *q; | |
206 | ||
207 | sigemptyset(&queue->signal); | |
208 | while (!list_empty(&queue->list)) { | |
209 | q = list_entry(queue->list.next, struct sigqueue , list); | |
210 | list_del_init(&q->list); | |
211 | __sigqueue_free(q); | |
212 | } | |
213 | } | |
214 | ||
215 | /* | |
216 | * Flush all pending signals for a task. | |
217 | */ | |
c81addc9 | 218 | void flush_signals(struct task_struct *t) |
1da177e4 LT |
219 | { |
220 | unsigned long flags; | |
221 | ||
222 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
f5264481 | 223 | clear_tsk_thread_flag(t, TIF_SIGPENDING); |
1da177e4 LT |
224 | flush_sigqueue(&t->pending); |
225 | flush_sigqueue(&t->signal->shared_pending); | |
226 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
227 | } | |
228 | ||
10ab825b ON |
229 | void ignore_signals(struct task_struct *t) |
230 | { | |
231 | int i; | |
232 | ||
233 | for (i = 0; i < _NSIG; ++i) | |
234 | t->sighand->action[i].sa.sa_handler = SIG_IGN; | |
235 | ||
236 | flush_signals(t); | |
237 | } | |
238 | ||
1da177e4 LT |
239 | /* |
240 | * Flush all handlers for a task. | |
241 | */ | |
242 | ||
243 | void | |
244 | flush_signal_handlers(struct task_struct *t, int force_default) | |
245 | { | |
246 | int i; | |
247 | struct k_sigaction *ka = &t->sighand->action[0]; | |
248 | for (i = _NSIG ; i != 0 ; i--) { | |
249 | if (force_default || ka->sa.sa_handler != SIG_IGN) | |
250 | ka->sa.sa_handler = SIG_DFL; | |
251 | ka->sa.sa_flags = 0; | |
252 | sigemptyset(&ka->sa.sa_mask); | |
253 | ka++; | |
254 | } | |
255 | } | |
256 | ||
abd4f750 MAS |
257 | int unhandled_signal(struct task_struct *tsk, int sig) |
258 | { | |
b460cbc5 | 259 | if (is_global_init(tsk)) |
abd4f750 MAS |
260 | return 1; |
261 | if (tsk->ptrace & PT_PTRACED) | |
262 | return 0; | |
263 | return (tsk->sighand->action[sig-1].sa.sa_handler == SIG_IGN) || | |
264 | (tsk->sighand->action[sig-1].sa.sa_handler == SIG_DFL); | |
265 | } | |
266 | ||
1da177e4 LT |
267 | |
268 | /* Notify the system that a driver wants to block all signals for this | |
269 | * process, and wants to be notified if any signals at all were to be | |
270 | * sent/acted upon. If the notifier routine returns non-zero, then the | |
271 | * signal will be acted upon after all. If the notifier routine returns 0, | |
272 | * then then signal will be blocked. Only one block per process is | |
273 | * allowed. priv is a pointer to private data that the notifier routine | |
274 | * can use to determine if the signal should be blocked or not. */ | |
275 | ||
276 | void | |
277 | block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask) | |
278 | { | |
279 | unsigned long flags; | |
280 | ||
281 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
282 | current->notifier_mask = mask; | |
283 | current->notifier_data = priv; | |
284 | current->notifier = notifier; | |
285 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
286 | } | |
287 | ||
288 | /* Notify the system that blocking has ended. */ | |
289 | ||
290 | void | |
291 | unblock_all_signals(void) | |
292 | { | |
293 | unsigned long flags; | |
294 | ||
295 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
296 | current->notifier = NULL; | |
297 | current->notifier_data = NULL; | |
298 | recalc_sigpending(); | |
299 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
300 | } | |
301 | ||
858119e1 | 302 | static int collect_signal(int sig, struct sigpending *list, siginfo_t *info) |
1da177e4 LT |
303 | { |
304 | struct sigqueue *q, *first = NULL; | |
305 | int still_pending = 0; | |
306 | ||
307 | if (unlikely(!sigismember(&list->signal, sig))) | |
308 | return 0; | |
309 | ||
310 | /* | |
311 | * Collect the siginfo appropriate to this signal. Check if | |
312 | * there is another siginfo for the same signal. | |
313 | */ | |
314 | list_for_each_entry(q, &list->list, list) { | |
315 | if (q->info.si_signo == sig) { | |
316 | if (first) { | |
317 | still_pending = 1; | |
318 | break; | |
319 | } | |
320 | first = q; | |
321 | } | |
322 | } | |
323 | if (first) { | |
324 | list_del_init(&first->list); | |
325 | copy_siginfo(info, &first->info); | |
326 | __sigqueue_free(first); | |
327 | if (!still_pending) | |
328 | sigdelset(&list->signal, sig); | |
329 | } else { | |
330 | ||
331 | /* Ok, it wasn't in the queue. This must be | |
332 | a fast-pathed signal or we must have been | |
333 | out of queue space. So zero out the info. | |
334 | */ | |
335 | sigdelset(&list->signal, sig); | |
336 | info->si_signo = sig; | |
337 | info->si_errno = 0; | |
338 | info->si_code = 0; | |
339 | info->si_pid = 0; | |
340 | info->si_uid = 0; | |
341 | } | |
342 | return 1; | |
343 | } | |
344 | ||
345 | static int __dequeue_signal(struct sigpending *pending, sigset_t *mask, | |
346 | siginfo_t *info) | |
347 | { | |
27d91e07 | 348 | int sig = next_signal(pending, mask); |
1da177e4 | 349 | |
1da177e4 LT |
350 | if (sig) { |
351 | if (current->notifier) { | |
352 | if (sigismember(current->notifier_mask, sig)) { | |
353 | if (!(current->notifier)(current->notifier_data)) { | |
354 | clear_thread_flag(TIF_SIGPENDING); | |
355 | return 0; | |
356 | } | |
357 | } | |
358 | } | |
359 | ||
360 | if (!collect_signal(sig, pending, info)) | |
361 | sig = 0; | |
1da177e4 | 362 | } |
1da177e4 LT |
363 | |
364 | return sig; | |
365 | } | |
366 | ||
367 | /* | |
368 | * Dequeue a signal and return the element to the caller, which is | |
369 | * expected to free it. | |
370 | * | |
371 | * All callers have to hold the siglock. | |
372 | */ | |
373 | int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info) | |
374 | { | |
caec4e8d BH |
375 | int signr = 0; |
376 | ||
377 | /* We only dequeue private signals from ourselves, we don't let | |
378 | * signalfd steal them | |
379 | */ | |
b8fceee1 | 380 | signr = __dequeue_signal(&tsk->pending, mask, info); |
8bfd9a7a | 381 | if (!signr) { |
1da177e4 LT |
382 | signr = __dequeue_signal(&tsk->signal->shared_pending, |
383 | mask, info); | |
8bfd9a7a TG |
384 | /* |
385 | * itimer signal ? | |
386 | * | |
387 | * itimers are process shared and we restart periodic | |
388 | * itimers in the signal delivery path to prevent DoS | |
389 | * attacks in the high resolution timer case. This is | |
390 | * compliant with the old way of self restarting | |
391 | * itimers, as the SIGALRM is a legacy signal and only | |
392 | * queued once. Changing the restart behaviour to | |
393 | * restart the timer in the signal dequeue path is | |
394 | * reducing the timer noise on heavy loaded !highres | |
395 | * systems too. | |
396 | */ | |
397 | if (unlikely(signr == SIGALRM)) { | |
398 | struct hrtimer *tmr = &tsk->signal->real_timer; | |
399 | ||
400 | if (!hrtimer_is_queued(tmr) && | |
401 | tsk->signal->it_real_incr.tv64 != 0) { | |
402 | hrtimer_forward(tmr, tmr->base->get_time(), | |
403 | tsk->signal->it_real_incr); | |
404 | hrtimer_restart(tmr); | |
405 | } | |
406 | } | |
407 | } | |
b8fceee1 | 408 | recalc_sigpending(); |
8bfd9a7a TG |
409 | if (signr && unlikely(sig_kernel_stop(signr))) { |
410 | /* | |
411 | * Set a marker that we have dequeued a stop signal. Our | |
412 | * caller might release the siglock and then the pending | |
413 | * stop signal it is about to process is no longer in the | |
414 | * pending bitmasks, but must still be cleared by a SIGCONT | |
415 | * (and overruled by a SIGKILL). So those cases clear this | |
416 | * shared flag after we've set it. Note that this flag may | |
417 | * remain set after the signal we return is ignored or | |
418 | * handled. That doesn't matter because its only purpose | |
419 | * is to alert stop-signal processing code when another | |
420 | * processor has come along and cleared the flag. | |
421 | */ | |
422 | if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT)) | |
423 | tsk->signal->flags |= SIGNAL_STOP_DEQUEUED; | |
424 | } | |
b8fceee1 | 425 | if (signr && |
1da177e4 | 426 | ((info->si_code & __SI_MASK) == __SI_TIMER) && |
f5264481 | 427 | info->si_sys_private) { |
1da177e4 LT |
428 | /* |
429 | * Release the siglock to ensure proper locking order | |
430 | * of timer locks outside of siglocks. Note, we leave | |
431 | * irqs disabled here, since the posix-timers code is | |
432 | * about to disable them again anyway. | |
433 | */ | |
434 | spin_unlock(&tsk->sighand->siglock); | |
435 | do_schedule_next_timer(info); | |
436 | spin_lock(&tsk->sighand->siglock); | |
437 | } | |
438 | return signr; | |
439 | } | |
440 | ||
441 | /* | |
442 | * Tell a process that it has a new active signal.. | |
443 | * | |
444 | * NOTE! we rely on the previous spin_lock to | |
445 | * lock interrupts for us! We can only be called with | |
446 | * "siglock" held, and the local interrupt must | |
447 | * have been disabled when that got acquired! | |
448 | * | |
449 | * No need to set need_resched since signal event passing | |
450 | * goes through ->blocked | |
451 | */ | |
452 | void signal_wake_up(struct task_struct *t, int resume) | |
453 | { | |
454 | unsigned int mask; | |
455 | ||
456 | set_tsk_thread_flag(t, TIF_SIGPENDING); | |
457 | ||
458 | /* | |
f021a3c2 MW |
459 | * For SIGKILL, we want to wake it up in the stopped/traced/killable |
460 | * case. We don't check t->state here because there is a race with it | |
1da177e4 LT |
461 | * executing another processor and just now entering stopped state. |
462 | * By using wake_up_state, we ensure the process will wake up and | |
463 | * handle its death signal. | |
464 | */ | |
465 | mask = TASK_INTERRUPTIBLE; | |
466 | if (resume) | |
f021a3c2 | 467 | mask |= TASK_WAKEKILL; |
1da177e4 LT |
468 | if (!wake_up_state(t, mask)) |
469 | kick_process(t); | |
470 | } | |
471 | ||
71fabd5e GA |
472 | /* |
473 | * Remove signals in mask from the pending set and queue. | |
474 | * Returns 1 if any signals were found. | |
475 | * | |
476 | * All callers must be holding the siglock. | |
477 | * | |
478 | * This version takes a sigset mask and looks at all signals, | |
479 | * not just those in the first mask word. | |
480 | */ | |
481 | static int rm_from_queue_full(sigset_t *mask, struct sigpending *s) | |
482 | { | |
483 | struct sigqueue *q, *n; | |
484 | sigset_t m; | |
485 | ||
486 | sigandsets(&m, mask, &s->signal); | |
487 | if (sigisemptyset(&m)) | |
488 | return 0; | |
489 | ||
490 | signandsets(&s->signal, &s->signal, mask); | |
491 | list_for_each_entry_safe(q, n, &s->list, list) { | |
492 | if (sigismember(mask, q->info.si_signo)) { | |
493 | list_del_init(&q->list); | |
494 | __sigqueue_free(q); | |
495 | } | |
496 | } | |
497 | return 1; | |
498 | } | |
1da177e4 LT |
499 | /* |
500 | * Remove signals in mask from the pending set and queue. | |
501 | * Returns 1 if any signals were found. | |
502 | * | |
503 | * All callers must be holding the siglock. | |
504 | */ | |
505 | static int rm_from_queue(unsigned long mask, struct sigpending *s) | |
506 | { | |
507 | struct sigqueue *q, *n; | |
508 | ||
509 | if (!sigtestsetmask(&s->signal, mask)) | |
510 | return 0; | |
511 | ||
512 | sigdelsetmask(&s->signal, mask); | |
513 | list_for_each_entry_safe(q, n, &s->list, list) { | |
514 | if (q->info.si_signo < SIGRTMIN && | |
515 | (mask & sigmask(q->info.si_signo))) { | |
516 | list_del_init(&q->list); | |
517 | __sigqueue_free(q); | |
518 | } | |
519 | } | |
520 | return 1; | |
521 | } | |
522 | ||
523 | /* | |
524 | * Bad permissions for sending the signal | |
525 | */ | |
526 | static int check_kill_permission(int sig, struct siginfo *info, | |
527 | struct task_struct *t) | |
528 | { | |
529 | int error = -EINVAL; | |
7ed20e1a | 530 | if (!valid_signal(sig)) |
1da177e4 | 531 | return error; |
e54dc243 | 532 | |
291041e9 AV |
533 | if (info == SEND_SIG_NOINFO || (!is_si_special(info) && SI_FROMUSER(info))) { |
534 | error = audit_signal_info(sig, t); /* Let audit system see the signal */ | |
535 | if (error) | |
536 | return error; | |
537 | error = -EPERM; | |
538 | if (((sig != SIGCONT) || | |
a47afb0f | 539 | (task_session_nr(current) != task_session_nr(t))) |
291041e9 AV |
540 | && (current->euid ^ t->suid) && (current->euid ^ t->uid) |
541 | && (current->uid ^ t->suid) && (current->uid ^ t->uid) | |
542 | && !capable(CAP_KILL)) | |
1da177e4 | 543 | return error; |
291041e9 | 544 | } |
c2f0c7c3 | 545 | |
e54dc243 | 546 | return security_task_kill(t, info, sig, 0); |
1da177e4 LT |
547 | } |
548 | ||
549 | /* forward decl */ | |
a1d5e21e | 550 | static void do_notify_parent_cldstop(struct task_struct *tsk, int why); |
1da177e4 LT |
551 | |
552 | /* | |
553 | * Handle magic process-wide effects of stop/continue signals. | |
554 | * Unlike the signal actions, these happen immediately at signal-generation | |
555 | * time regardless of blocking, ignoring, or handling. This does the | |
556 | * actual continuing for SIGCONT, but not the actual stopping for stop | |
557 | * signals. The process stop is done as a signal action for SIG_DFL. | |
558 | */ | |
559 | static void handle_stop_signal(int sig, struct task_struct *p) | |
560 | { | |
561 | struct task_struct *t; | |
562 | ||
dd12f48d | 563 | if (p->signal->flags & SIGNAL_GROUP_EXIT) |
1da177e4 LT |
564 | /* |
565 | * The process is in the middle of dying already. | |
566 | */ | |
567 | return; | |
568 | ||
569 | if (sig_kernel_stop(sig)) { | |
570 | /* | |
571 | * This is a stop signal. Remove SIGCONT from all queues. | |
572 | */ | |
573 | rm_from_queue(sigmask(SIGCONT), &p->signal->shared_pending); | |
574 | t = p; | |
575 | do { | |
576 | rm_from_queue(sigmask(SIGCONT), &t->pending); | |
577 | t = next_thread(t); | |
578 | } while (t != p); | |
579 | } else if (sig == SIGCONT) { | |
580 | /* | |
581 | * Remove all stop signals from all queues, | |
582 | * and wake all threads. | |
583 | */ | |
584 | if (unlikely(p->signal->group_stop_count > 0)) { | |
585 | /* | |
586 | * There was a group stop in progress. We'll | |
587 | * pretend it finished before we got here. We are | |
588 | * obliged to report it to the parent: if the | |
589 | * SIGSTOP happened "after" this SIGCONT, then it | |
590 | * would have cleared this pending SIGCONT. If it | |
591 | * happened "before" this SIGCONT, then the parent | |
592 | * got the SIGCHLD about the stop finishing before | |
593 | * the continue happened. We do the notification | |
594 | * now, and it's as if the stop had finished and | |
595 | * the SIGCHLD was pending on entry to this kill. | |
596 | */ | |
597 | p->signal->group_stop_count = 0; | |
598 | p->signal->flags = SIGNAL_STOP_CONTINUED; | |
599 | spin_unlock(&p->sighand->siglock); | |
a1d5e21e | 600 | do_notify_parent_cldstop(p, CLD_STOPPED); |
1da177e4 LT |
601 | spin_lock(&p->sighand->siglock); |
602 | } | |
603 | rm_from_queue(SIG_KERNEL_STOP_MASK, &p->signal->shared_pending); | |
604 | t = p; | |
605 | do { | |
606 | unsigned int state; | |
607 | rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending); | |
608 | ||
609 | /* | |
610 | * If there is a handler for SIGCONT, we must make | |
611 | * sure that no thread returns to user mode before | |
612 | * we post the signal, in case it was the only | |
613 | * thread eligible to run the signal handler--then | |
614 | * it must not do anything between resuming and | |
615 | * running the handler. With the TIF_SIGPENDING | |
616 | * flag set, the thread will pause and acquire the | |
617 | * siglock that we hold now and until we've queued | |
618 | * the pending signal. | |
619 | * | |
620 | * Wake up the stopped thread _after_ setting | |
621 | * TIF_SIGPENDING | |
622 | */ | |
f021a3c2 | 623 | state = __TASK_STOPPED; |
1da177e4 LT |
624 | if (sig_user_defined(t, SIGCONT) && !sigismember(&t->blocked, SIGCONT)) { |
625 | set_tsk_thread_flag(t, TIF_SIGPENDING); | |
626 | state |= TASK_INTERRUPTIBLE; | |
627 | } | |
628 | wake_up_state(t, state); | |
629 | ||
630 | t = next_thread(t); | |
631 | } while (t != p); | |
632 | ||
633 | if (p->signal->flags & SIGNAL_STOP_STOPPED) { | |
634 | /* | |
635 | * We were in fact stopped, and are now continued. | |
636 | * Notify the parent with CLD_CONTINUED. | |
637 | */ | |
638 | p->signal->flags = SIGNAL_STOP_CONTINUED; | |
639 | p->signal->group_exit_code = 0; | |
640 | spin_unlock(&p->sighand->siglock); | |
a1d5e21e | 641 | do_notify_parent_cldstop(p, CLD_CONTINUED); |
1da177e4 LT |
642 | spin_lock(&p->sighand->siglock); |
643 | } else { | |
644 | /* | |
645 | * We are not stopped, but there could be a stop | |
646 | * signal in the middle of being processed after | |
647 | * being removed from the queue. Clear that too. | |
648 | */ | |
649 | p->signal->flags = 0; | |
650 | } | |
651 | } else if (sig == SIGKILL) { | |
652 | /* | |
653 | * Make sure that any pending stop signal already dequeued | |
654 | * is undone by the wakeup for SIGKILL. | |
655 | */ | |
656 | p->signal->flags = 0; | |
657 | } | |
658 | } | |
659 | ||
af7fff9c PE |
660 | static inline int legacy_queue(struct sigpending *signals, int sig) |
661 | { | |
662 | return (sig < SIGRTMIN) && sigismember(&signals->signal, sig); | |
663 | } | |
664 | ||
1da177e4 LT |
665 | static int send_signal(int sig, struct siginfo *info, struct task_struct *t, |
666 | struct sigpending *signals) | |
667 | { | |
668 | struct sigqueue * q = NULL; | |
1da177e4 | 669 | |
fba2afaa DL |
670 | /* |
671 | * Deliver the signal to listening signalfds. This must be called | |
672 | * with the sighand lock held. | |
673 | */ | |
674 | signalfd_notify(t, sig); | |
675 | ||
1da177e4 LT |
676 | /* |
677 | * fast-pathed signals for kernel-internal things like SIGSTOP | |
678 | * or SIGKILL. | |
679 | */ | |
b67a1b9e | 680 | if (info == SEND_SIG_FORCED) |
1da177e4 LT |
681 | goto out_set; |
682 | ||
683 | /* Real-time signals must be queued if sent by sigqueue, or | |
684 | some other real-time mechanism. It is implementation | |
685 | defined whether kill() does so. We attempt to do so, on | |
686 | the principle of least surprise, but since kill is not | |
687 | allowed to fail with EAGAIN when low on memory we just | |
688 | make sure at least one signal gets delivered and don't | |
689 | pass on the info struct. */ | |
690 | ||
691 | q = __sigqueue_alloc(t, GFP_ATOMIC, (sig < SIGRTMIN && | |
621d3121 | 692 | (is_si_special(info) || |
1da177e4 LT |
693 | info->si_code >= 0))); |
694 | if (q) { | |
695 | list_add_tail(&q->list, &signals->list); | |
696 | switch ((unsigned long) info) { | |
b67a1b9e | 697 | case (unsigned long) SEND_SIG_NOINFO: |
1da177e4 LT |
698 | q->info.si_signo = sig; |
699 | q->info.si_errno = 0; | |
700 | q->info.si_code = SI_USER; | |
b488893a | 701 | q->info.si_pid = task_pid_vnr(current); |
1da177e4 LT |
702 | q->info.si_uid = current->uid; |
703 | break; | |
b67a1b9e | 704 | case (unsigned long) SEND_SIG_PRIV: |
1da177e4 LT |
705 | q->info.si_signo = sig; |
706 | q->info.si_errno = 0; | |
707 | q->info.si_code = SI_KERNEL; | |
708 | q->info.si_pid = 0; | |
709 | q->info.si_uid = 0; | |
710 | break; | |
711 | default: | |
712 | copy_siginfo(&q->info, info); | |
713 | break; | |
714 | } | |
621d3121 ON |
715 | } else if (!is_si_special(info)) { |
716 | if (sig >= SIGRTMIN && info->si_code != SI_USER) | |
1da177e4 LT |
717 | /* |
718 | * Queue overflow, abort. We may abort if the signal was rt | |
719 | * and sent by user using something other than kill(). | |
720 | */ | |
721 | return -EAGAIN; | |
1da177e4 LT |
722 | } |
723 | ||
724 | out_set: | |
725 | sigaddset(&signals->signal, sig); | |
e1401c6b | 726 | return 0; |
1da177e4 LT |
727 | } |
728 | ||
45807a1d IM |
729 | int print_fatal_signals; |
730 | ||
731 | static void print_fatal_signal(struct pt_regs *regs, int signr) | |
732 | { | |
733 | printk("%s/%d: potentially unexpected fatal signal %d.\n", | |
ba25f9dc | 734 | current->comm, task_pid_nr(current), signr); |
45807a1d | 735 | |
ca5cd877 | 736 | #if defined(__i386__) && !defined(__arch_um__) |
65ea5b03 | 737 | printk("code at %08lx: ", regs->ip); |
45807a1d IM |
738 | { |
739 | int i; | |
740 | for (i = 0; i < 16; i++) { | |
741 | unsigned char insn; | |
742 | ||
65ea5b03 | 743 | __get_user(insn, (unsigned char *)(regs->ip + i)); |
45807a1d IM |
744 | printk("%02x ", insn); |
745 | } | |
746 | } | |
747 | #endif | |
748 | printk("\n"); | |
749 | show_regs(regs); | |
750 | } | |
751 | ||
752 | static int __init setup_print_fatal_signals(char *str) | |
753 | { | |
754 | get_option (&str, &print_fatal_signals); | |
755 | ||
756 | return 1; | |
757 | } | |
758 | ||
759 | __setup("print-fatal-signals=", setup_print_fatal_signals); | |
1da177e4 LT |
760 | |
761 | static int | |
762 | specific_send_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
763 | { | |
764 | int ret = 0; | |
765 | ||
fda8bd78 | 766 | BUG_ON(!irqs_disabled()); |
1da177e4 LT |
767 | assert_spin_locked(&t->sighand->siglock); |
768 | ||
1da177e4 LT |
769 | /* Short-circuit ignored signals. */ |
770 | if (sig_ignored(t, sig)) | |
771 | goto out; | |
772 | ||
773 | /* Support queueing exactly one non-rt signal, so that we | |
774 | can get more detailed information about the cause of | |
775 | the signal. */ | |
af7fff9c | 776 | if (legacy_queue(&t->pending, sig)) |
1da177e4 LT |
777 | goto out; |
778 | ||
779 | ret = send_signal(sig, info, t, &t->pending); | |
780 | if (!ret && !sigismember(&t->blocked, sig)) | |
781 | signal_wake_up(t, sig == SIGKILL); | |
782 | out: | |
783 | return ret; | |
784 | } | |
785 | ||
786 | /* | |
787 | * Force a signal that the process can't ignore: if necessary | |
788 | * we unblock the signal and change any SIG_IGN to SIG_DFL. | |
ae74c3b6 LT |
789 | * |
790 | * Note: If we unblock the signal, we always reset it to SIG_DFL, | |
791 | * since we do not want to have a signal handler that was blocked | |
792 | * be invoked when user space had explicitly blocked it. | |
793 | * | |
794 | * We don't want to have recursive SIGSEGV's etc, for example. | |
1da177e4 | 795 | */ |
1da177e4 LT |
796 | int |
797 | force_sig_info(int sig, struct siginfo *info, struct task_struct *t) | |
798 | { | |
799 | unsigned long int flags; | |
ae74c3b6 LT |
800 | int ret, blocked, ignored; |
801 | struct k_sigaction *action; | |
1da177e4 LT |
802 | |
803 | spin_lock_irqsave(&t->sighand->siglock, flags); | |
ae74c3b6 LT |
804 | action = &t->sighand->action[sig-1]; |
805 | ignored = action->sa.sa_handler == SIG_IGN; | |
806 | blocked = sigismember(&t->blocked, sig); | |
807 | if (blocked || ignored) { | |
808 | action->sa.sa_handler = SIG_DFL; | |
809 | if (blocked) { | |
810 | sigdelset(&t->blocked, sig); | |
7bb44ade | 811 | recalc_sigpending_and_wake(t); |
ae74c3b6 | 812 | } |
1da177e4 LT |
813 | } |
814 | ret = specific_send_sig_info(sig, info, t); | |
815 | spin_unlock_irqrestore(&t->sighand->siglock, flags); | |
816 | ||
817 | return ret; | |
818 | } | |
819 | ||
820 | void | |
821 | force_sig_specific(int sig, struct task_struct *t) | |
822 | { | |
b0423a0d | 823 | force_sig_info(sig, SEND_SIG_FORCED, t); |
1da177e4 LT |
824 | } |
825 | ||
826 | /* | |
827 | * Test if P wants to take SIG. After we've checked all threads with this, | |
828 | * it's equivalent to finding no threads not blocking SIG. Any threads not | |
829 | * blocking SIG were ruled out because they are not running and already | |
830 | * have pending signals. Such threads will dequeue from the shared queue | |
831 | * as soon as they're available, so putting the signal on the shared queue | |
832 | * will be equivalent to sending it to one such thread. | |
833 | */ | |
188a1eaf LT |
834 | static inline int wants_signal(int sig, struct task_struct *p) |
835 | { | |
836 | if (sigismember(&p->blocked, sig)) | |
837 | return 0; | |
838 | if (p->flags & PF_EXITING) | |
839 | return 0; | |
840 | if (sig == SIGKILL) | |
841 | return 1; | |
e1abb39c | 842 | if (task_is_stopped_or_traced(p)) |
188a1eaf LT |
843 | return 0; |
844 | return task_curr(p) || !signal_pending(p); | |
845 | } | |
1da177e4 LT |
846 | |
847 | static void | |
848 | __group_complete_signal(int sig, struct task_struct *p) | |
849 | { | |
1da177e4 LT |
850 | struct task_struct *t; |
851 | ||
1da177e4 LT |
852 | /* |
853 | * Now find a thread we can wake up to take the signal off the queue. | |
854 | * | |
855 | * If the main thread wants the signal, it gets first crack. | |
856 | * Probably the least surprising to the average bear. | |
857 | */ | |
188a1eaf | 858 | if (wants_signal(sig, p)) |
1da177e4 LT |
859 | t = p; |
860 | else if (thread_group_empty(p)) | |
861 | /* | |
862 | * There is just one thread and it does not need to be woken. | |
863 | * It will dequeue unblocked signals before it runs again. | |
864 | */ | |
865 | return; | |
866 | else { | |
867 | /* | |
868 | * Otherwise try to find a suitable thread. | |
869 | */ | |
870 | t = p->signal->curr_target; | |
871 | if (t == NULL) | |
872 | /* restart balancing at this thread */ | |
873 | t = p->signal->curr_target = p; | |
1da177e4 | 874 | |
188a1eaf | 875 | while (!wants_signal(sig, t)) { |
1da177e4 LT |
876 | t = next_thread(t); |
877 | if (t == p->signal->curr_target) | |
878 | /* | |
879 | * No thread needs to be woken. | |
880 | * Any eligible threads will see | |
881 | * the signal in the queue soon. | |
882 | */ | |
883 | return; | |
884 | } | |
885 | p->signal->curr_target = t; | |
886 | } | |
887 | ||
888 | /* | |
889 | * Found a killable thread. If the signal will be fatal, | |
890 | * then start taking the whole group down immediately. | |
891 | */ | |
892 | if (sig_fatal(p, sig) && !(p->signal->flags & SIGNAL_GROUP_EXIT) && | |
893 | !sigismember(&t->real_blocked, sig) && | |
894 | (sig == SIGKILL || !(t->ptrace & PT_PTRACED))) { | |
895 | /* | |
896 | * This signal will be fatal to the whole group. | |
897 | */ | |
898 | if (!sig_kernel_coredump(sig)) { | |
899 | /* | |
900 | * Start a group exit and wake everybody up. | |
901 | * This way we don't have other threads | |
902 | * running and doing things after a slower | |
903 | * thread has the fatal signal pending. | |
904 | */ | |
905 | p->signal->flags = SIGNAL_GROUP_EXIT; | |
906 | p->signal->group_exit_code = sig; | |
907 | p->signal->group_stop_count = 0; | |
908 | t = p; | |
909 | do { | |
910 | sigaddset(&t->pending.signal, SIGKILL); | |
911 | signal_wake_up(t, 1); | |
18442cf2 | 912 | } while_each_thread(p, t); |
1da177e4 LT |
913 | return; |
914 | } | |
1da177e4 LT |
915 | } |
916 | ||
917 | /* | |
918 | * The signal is already in the shared-pending queue. | |
919 | * Tell the chosen thread to wake up and dequeue it. | |
920 | */ | |
921 | signal_wake_up(t, sig == SIGKILL); | |
922 | return; | |
923 | } | |
924 | ||
925 | int | |
926 | __group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
927 | { | |
928 | int ret = 0; | |
929 | ||
930 | assert_spin_locked(&p->sighand->siglock); | |
931 | handle_stop_signal(sig, p); | |
932 | ||
1da177e4 LT |
933 | /* Short-circuit ignored signals. */ |
934 | if (sig_ignored(p, sig)) | |
935 | return ret; | |
936 | ||
af7fff9c | 937 | if (legacy_queue(&p->signal->shared_pending, sig)) |
1da177e4 LT |
938 | /* This is a non-RT signal and we already have one queued. */ |
939 | return ret; | |
940 | ||
941 | /* | |
942 | * Put this signal on the shared-pending queue, or fail with EAGAIN. | |
943 | * We always use the shared queue for process-wide signals, | |
944 | * to avoid several races. | |
945 | */ | |
946 | ret = send_signal(sig, info, p, &p->signal->shared_pending); | |
947 | if (unlikely(ret)) | |
948 | return ret; | |
949 | ||
950 | __group_complete_signal(sig, p); | |
951 | return 0; | |
952 | } | |
953 | ||
954 | /* | |
955 | * Nuke all other threads in the group. | |
956 | */ | |
957 | void zap_other_threads(struct task_struct *p) | |
958 | { | |
959 | struct task_struct *t; | |
960 | ||
1da177e4 LT |
961 | p->signal->group_stop_count = 0; |
962 | ||
1da177e4 LT |
963 | for (t = next_thread(p); t != p; t = next_thread(t)) { |
964 | /* | |
965 | * Don't bother with already dead threads | |
966 | */ | |
967 | if (t->exit_state) | |
968 | continue; | |
969 | ||
30e0fca6 | 970 | /* SIGKILL will be handled before any pending SIGSTOP */ |
1da177e4 | 971 | sigaddset(&t->pending.signal, SIGKILL); |
1da177e4 LT |
972 | signal_wake_up(t, 1); |
973 | } | |
974 | } | |
975 | ||
b5606c2d | 976 | int __fatal_signal_pending(struct task_struct *tsk) |
f776d12d MW |
977 | { |
978 | return sigismember(&tsk->pending.signal, SIGKILL); | |
979 | } | |
13f09b95 | 980 | EXPORT_SYMBOL(__fatal_signal_pending); |
f776d12d | 981 | |
1da177e4 | 982 | /* |
e56d0903 | 983 | * Must be called under rcu_read_lock() or with tasklist_lock read-held. |
1da177e4 | 984 | */ |
f63ee72e ON |
985 | struct sighand_struct *lock_task_sighand(struct task_struct *tsk, unsigned long *flags) |
986 | { | |
987 | struct sighand_struct *sighand; | |
988 | ||
989 | for (;;) { | |
990 | sighand = rcu_dereference(tsk->sighand); | |
991 | if (unlikely(sighand == NULL)) | |
992 | break; | |
993 | ||
994 | spin_lock_irqsave(&sighand->siglock, *flags); | |
995 | if (likely(sighand == tsk->sighand)) | |
996 | break; | |
997 | spin_unlock_irqrestore(&sighand->siglock, *flags); | |
998 | } | |
999 | ||
1000 | return sighand; | |
1001 | } | |
1002 | ||
1da177e4 LT |
1003 | int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p) |
1004 | { | |
1005 | unsigned long flags; | |
1006 | int ret; | |
1007 | ||
1008 | ret = check_kill_permission(sig, info, p); | |
f63ee72e ON |
1009 | |
1010 | if (!ret && sig) { | |
1011 | ret = -ESRCH; | |
1012 | if (lock_task_sighand(p, &flags)) { | |
1013 | ret = __group_send_sig_info(sig, info, p); | |
1014 | unlock_task_sighand(p, &flags); | |
2d89c929 | 1015 | } |
1da177e4 LT |
1016 | } |
1017 | ||
1018 | return ret; | |
1019 | } | |
1020 | ||
1021 | /* | |
146a505d | 1022 | * __kill_pgrp_info() sends a signal to a process group: this is what the tty |
1da177e4 LT |
1023 | * control characters do (^C, ^Z etc) |
1024 | */ | |
1025 | ||
c4b92fc1 | 1026 | int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp) |
1da177e4 LT |
1027 | { |
1028 | struct task_struct *p = NULL; | |
1029 | int retval, success; | |
1030 | ||
1da177e4 LT |
1031 | success = 0; |
1032 | retval = -ESRCH; | |
c4b92fc1 | 1033 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
1da177e4 LT |
1034 | int err = group_send_sig_info(sig, info, p); |
1035 | success |= !err; | |
1036 | retval = err; | |
c4b92fc1 | 1037 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
1da177e4 LT |
1038 | return success ? 0 : retval; |
1039 | } | |
1040 | ||
c4b92fc1 | 1041 | int kill_pid_info(int sig, struct siginfo *info, struct pid *pid) |
1da177e4 | 1042 | { |
d36174bc | 1043 | int error = -ESRCH; |
1da177e4 LT |
1044 | struct task_struct *p; |
1045 | ||
e56d0903 | 1046 | rcu_read_lock(); |
0c12b517 | 1047 | if (unlikely(sig_needs_tasklist(sig))) |
e56d0903 | 1048 | read_lock(&tasklist_lock); |
0c12b517 | 1049 | |
d36174bc | 1050 | retry: |
c4b92fc1 | 1051 | p = pid_task(pid, PIDTYPE_PID); |
d36174bc | 1052 | if (p) { |
1da177e4 | 1053 | error = group_send_sig_info(sig, info, p); |
d36174bc ON |
1054 | if (unlikely(error == -ESRCH)) |
1055 | /* | |
1056 | * The task was unhashed in between, try again. | |
1057 | * If it is dead, pid_task() will return NULL, | |
1058 | * if we race with de_thread() it will find the | |
1059 | * new leader. | |
1060 | */ | |
1061 | goto retry; | |
1062 | } | |
0c12b517 ON |
1063 | |
1064 | if (unlikely(sig_needs_tasklist(sig))) | |
e56d0903 IM |
1065 | read_unlock(&tasklist_lock); |
1066 | rcu_read_unlock(); | |
1da177e4 LT |
1067 | return error; |
1068 | } | |
1069 | ||
c3de4b38 MW |
1070 | int |
1071 | kill_proc_info(int sig, struct siginfo *info, pid_t pid) | |
c4b92fc1 EB |
1072 | { |
1073 | int error; | |
1074 | rcu_read_lock(); | |
b488893a | 1075 | error = kill_pid_info(sig, info, find_vpid(pid)); |
c4b92fc1 EB |
1076 | rcu_read_unlock(); |
1077 | return error; | |
1078 | } | |
1079 | ||
2425c08b EB |
1080 | /* like kill_pid_info(), but doesn't use uid/euid of "current" */ |
1081 | int kill_pid_info_as_uid(int sig, struct siginfo *info, struct pid *pid, | |
8f95dc58 | 1082 | uid_t uid, uid_t euid, u32 secid) |
46113830 HW |
1083 | { |
1084 | int ret = -EINVAL; | |
1085 | struct task_struct *p; | |
1086 | ||
1087 | if (!valid_signal(sig)) | |
1088 | return ret; | |
1089 | ||
1090 | read_lock(&tasklist_lock); | |
2425c08b | 1091 | p = pid_task(pid, PIDTYPE_PID); |
46113830 HW |
1092 | if (!p) { |
1093 | ret = -ESRCH; | |
1094 | goto out_unlock; | |
1095 | } | |
0811af28 | 1096 | if ((info == SEND_SIG_NOINFO || (!is_si_special(info) && SI_FROMUSER(info))) |
46113830 HW |
1097 | && (euid != p->suid) && (euid != p->uid) |
1098 | && (uid != p->suid) && (uid != p->uid)) { | |
1099 | ret = -EPERM; | |
1100 | goto out_unlock; | |
1101 | } | |
8f95dc58 DQ |
1102 | ret = security_task_kill(p, info, sig, secid); |
1103 | if (ret) | |
1104 | goto out_unlock; | |
46113830 HW |
1105 | if (sig && p->sighand) { |
1106 | unsigned long flags; | |
1107 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1108 | ret = __group_send_sig_info(sig, info, p); | |
1109 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1110 | } | |
1111 | out_unlock: | |
1112 | read_unlock(&tasklist_lock); | |
1113 | return ret; | |
1114 | } | |
2425c08b | 1115 | EXPORT_SYMBOL_GPL(kill_pid_info_as_uid); |
1da177e4 LT |
1116 | |
1117 | /* | |
1118 | * kill_something_info() interprets pid in interesting ways just like kill(2). | |
1119 | * | |
1120 | * POSIX specifies that kill(-1,sig) is unspecified, but what we have | |
1121 | * is probably wrong. Should make it like BSD or SYSV. | |
1122 | */ | |
1123 | ||
1124 | static int kill_something_info(int sig, struct siginfo *info, int pid) | |
1125 | { | |
8d42db18 | 1126 | int ret; |
d5df763b PE |
1127 | |
1128 | if (pid > 0) { | |
1129 | rcu_read_lock(); | |
1130 | ret = kill_pid_info(sig, info, find_vpid(pid)); | |
1131 | rcu_read_unlock(); | |
1132 | return ret; | |
1133 | } | |
1134 | ||
1135 | read_lock(&tasklist_lock); | |
1136 | if (pid != -1) { | |
1137 | ret = __kill_pgrp_info(sig, info, | |
1138 | pid ? find_vpid(-pid) : task_pgrp(current)); | |
1139 | } else { | |
1da177e4 LT |
1140 | int retval = 0, count = 0; |
1141 | struct task_struct * p; | |
1142 | ||
1da177e4 | 1143 | for_each_process(p) { |
bac0abd6 | 1144 | if (p->pid > 1 && !same_thread_group(p, current)) { |
1da177e4 LT |
1145 | int err = group_send_sig_info(sig, info, p); |
1146 | ++count; | |
1147 | if (err != -EPERM) | |
1148 | retval = err; | |
1149 | } | |
1150 | } | |
8d42db18 | 1151 | ret = count ? retval : -ESRCH; |
1da177e4 | 1152 | } |
d5df763b PE |
1153 | read_unlock(&tasklist_lock); |
1154 | ||
8d42db18 | 1155 | return ret; |
1da177e4 LT |
1156 | } |
1157 | ||
1158 | /* | |
1159 | * These are for backward compatibility with the rest of the kernel source. | |
1160 | */ | |
1161 | ||
1162 | /* | |
1163 | * These two are the most common entry points. They send a signal | |
1164 | * just to the specific thread. | |
1165 | */ | |
1166 | int | |
1167 | send_sig_info(int sig, struct siginfo *info, struct task_struct *p) | |
1168 | { | |
1169 | int ret; | |
1170 | unsigned long flags; | |
1171 | ||
1172 | /* | |
1173 | * Make sure legacy kernel users don't send in bad values | |
1174 | * (normal paths check this in check_kill_permission). | |
1175 | */ | |
7ed20e1a | 1176 | if (!valid_signal(sig)) |
1da177e4 LT |
1177 | return -EINVAL; |
1178 | ||
1179 | /* | |
1180 | * We need the tasklist lock even for the specific | |
1181 | * thread case (when we don't need to follow the group | |
1182 | * lists) in order to avoid races with "p->sighand" | |
1183 | * going away or changing from under us. | |
1184 | */ | |
1185 | read_lock(&tasklist_lock); | |
1186 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1187 | ret = specific_send_sig_info(sig, info, p); | |
1188 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1189 | read_unlock(&tasklist_lock); | |
1190 | return ret; | |
1191 | } | |
1192 | ||
b67a1b9e ON |
1193 | #define __si_special(priv) \ |
1194 | ((priv) ? SEND_SIG_PRIV : SEND_SIG_NOINFO) | |
1195 | ||
1da177e4 LT |
1196 | int |
1197 | send_sig(int sig, struct task_struct *p, int priv) | |
1198 | { | |
b67a1b9e | 1199 | return send_sig_info(sig, __si_special(priv), p); |
1da177e4 LT |
1200 | } |
1201 | ||
1da177e4 LT |
1202 | void |
1203 | force_sig(int sig, struct task_struct *p) | |
1204 | { | |
b67a1b9e | 1205 | force_sig_info(sig, SEND_SIG_PRIV, p); |
1da177e4 LT |
1206 | } |
1207 | ||
1208 | /* | |
1209 | * When things go south during signal handling, we | |
1210 | * will force a SIGSEGV. And if the signal that caused | |
1211 | * the problem was already a SIGSEGV, we'll want to | |
1212 | * make sure we don't even try to deliver the signal.. | |
1213 | */ | |
1214 | int | |
1215 | force_sigsegv(int sig, struct task_struct *p) | |
1216 | { | |
1217 | if (sig == SIGSEGV) { | |
1218 | unsigned long flags; | |
1219 | spin_lock_irqsave(&p->sighand->siglock, flags); | |
1220 | p->sighand->action[sig - 1].sa.sa_handler = SIG_DFL; | |
1221 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1222 | } | |
1223 | force_sig(SIGSEGV, p); | |
1224 | return 0; | |
1225 | } | |
1226 | ||
c4b92fc1 EB |
1227 | int kill_pgrp(struct pid *pid, int sig, int priv) |
1228 | { | |
146a505d PE |
1229 | int ret; |
1230 | ||
1231 | read_lock(&tasklist_lock); | |
1232 | ret = __kill_pgrp_info(sig, __si_special(priv), pid); | |
1233 | read_unlock(&tasklist_lock); | |
1234 | ||
1235 | return ret; | |
c4b92fc1 EB |
1236 | } |
1237 | EXPORT_SYMBOL(kill_pgrp); | |
1238 | ||
1239 | int kill_pid(struct pid *pid, int sig, int priv) | |
1240 | { | |
1241 | return kill_pid_info(sig, __si_special(priv), pid); | |
1242 | } | |
1243 | EXPORT_SYMBOL(kill_pid); | |
1244 | ||
1da177e4 LT |
1245 | int |
1246 | kill_proc(pid_t pid, int sig, int priv) | |
1247 | { | |
b488893a PE |
1248 | int ret; |
1249 | ||
1250 | rcu_read_lock(); | |
1251 | ret = kill_pid_info(sig, __si_special(priv), find_pid(pid)); | |
1252 | rcu_read_unlock(); | |
1253 | return ret; | |
1da177e4 LT |
1254 | } |
1255 | ||
1256 | /* | |
1257 | * These functions support sending signals using preallocated sigqueue | |
1258 | * structures. This is needed "because realtime applications cannot | |
1259 | * afford to lose notifications of asynchronous events, like timer | |
1260 | * expirations or I/O completions". In the case of Posix Timers | |
1261 | * we allocate the sigqueue structure from the timer_create. If this | |
1262 | * allocation fails we are able to report the failure to the application | |
1263 | * with an EAGAIN error. | |
1264 | */ | |
1265 | ||
1266 | struct sigqueue *sigqueue_alloc(void) | |
1267 | { | |
1268 | struct sigqueue *q; | |
1269 | ||
1270 | if ((q = __sigqueue_alloc(current, GFP_KERNEL, 0))) | |
1271 | q->flags |= SIGQUEUE_PREALLOC; | |
1272 | return(q); | |
1273 | } | |
1274 | ||
1275 | void sigqueue_free(struct sigqueue *q) | |
1276 | { | |
1277 | unsigned long flags; | |
60187d27 ON |
1278 | spinlock_t *lock = ¤t->sighand->siglock; |
1279 | ||
1da177e4 LT |
1280 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
1281 | /* | |
1282 | * If the signal is still pending remove it from the | |
60187d27 ON |
1283 | * pending queue. We must hold ->siglock while testing |
1284 | * q->list to serialize with collect_signal(). | |
1da177e4 | 1285 | */ |
60187d27 ON |
1286 | spin_lock_irqsave(lock, flags); |
1287 | if (!list_empty(&q->list)) | |
1288 | list_del_init(&q->list); | |
1289 | spin_unlock_irqrestore(lock, flags); | |
1290 | ||
1da177e4 LT |
1291 | q->flags &= ~SIGQUEUE_PREALLOC; |
1292 | __sigqueue_free(q); | |
1293 | } | |
1294 | ||
54767908 | 1295 | int send_sigqueue(int sig, struct sigqueue *q, struct task_struct *p) |
1da177e4 LT |
1296 | { |
1297 | unsigned long flags; | |
1298 | int ret = 0; | |
1299 | ||
1da177e4 | 1300 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); |
e56d0903 IM |
1301 | |
1302 | /* | |
1303 | * The rcu based delayed sighand destroy makes it possible to | |
1304 | * run this without tasklist lock held. The task struct itself | |
1305 | * cannot go away as create_timer did get_task_struct(). | |
1306 | * | |
1307 | * We return -1, when the task is marked exiting, so | |
1308 | * posix_timer_event can redirect it to the group leader | |
1309 | */ | |
1310 | rcu_read_lock(); | |
e752dd6c | 1311 | |
54767908 | 1312 | if (!likely(lock_task_sighand(p, &flags))) { |
e752dd6c ON |
1313 | ret = -1; |
1314 | goto out_err; | |
1315 | } | |
1316 | ||
1da177e4 LT |
1317 | if (unlikely(!list_empty(&q->list))) { |
1318 | /* | |
1319 | * If an SI_TIMER entry is already queue just increment | |
1320 | * the overrun count. | |
1321 | */ | |
54767908 | 1322 | BUG_ON(q->info.si_code != SI_TIMER); |
1da177e4 LT |
1323 | q->info.si_overrun++; |
1324 | goto out; | |
e752dd6c | 1325 | } |
1da177e4 LT |
1326 | /* Short-circuit ignored signals. */ |
1327 | if (sig_ignored(p, sig)) { | |
1328 | ret = 1; | |
1329 | goto out; | |
1330 | } | |
fba2afaa DL |
1331 | /* |
1332 | * Deliver the signal to listening signalfds. This must be called | |
1333 | * with the sighand lock held. | |
1334 | */ | |
1335 | signalfd_notify(p, sig); | |
1da177e4 | 1336 | |
1da177e4 LT |
1337 | list_add_tail(&q->list, &p->pending.list); |
1338 | sigaddset(&p->pending.signal, sig); | |
1339 | if (!sigismember(&p->blocked, sig)) | |
1340 | signal_wake_up(p, sig == SIGKILL); | |
1341 | ||
1342 | out: | |
54767908 | 1343 | unlock_task_sighand(p, &flags); |
e752dd6c | 1344 | out_err: |
e56d0903 | 1345 | rcu_read_unlock(); |
e752dd6c ON |
1346 | |
1347 | return ret; | |
1da177e4 LT |
1348 | } |
1349 | ||
1350 | int | |
1351 | send_group_sigqueue(int sig, struct sigqueue *q, struct task_struct *p) | |
1352 | { | |
1353 | unsigned long flags; | |
1354 | int ret = 0; | |
1355 | ||
1356 | BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); | |
e56d0903 | 1357 | |
1da177e4 | 1358 | read_lock(&tasklist_lock); |
e56d0903 | 1359 | /* Since it_lock is held, p->sighand cannot be NULL. */ |
1da177e4 LT |
1360 | spin_lock_irqsave(&p->sighand->siglock, flags); |
1361 | handle_stop_signal(sig, p); | |
1362 | ||
1363 | /* Short-circuit ignored signals. */ | |
1364 | if (sig_ignored(p, sig)) { | |
1365 | ret = 1; | |
1366 | goto out; | |
1367 | } | |
1368 | ||
1369 | if (unlikely(!list_empty(&q->list))) { | |
1370 | /* | |
1371 | * If an SI_TIMER entry is already queue just increment | |
1372 | * the overrun count. Other uses should not try to | |
1373 | * send the signal multiple times. | |
1374 | */ | |
fda8bd78 | 1375 | BUG_ON(q->info.si_code != SI_TIMER); |
1da177e4 LT |
1376 | q->info.si_overrun++; |
1377 | goto out; | |
1378 | } | |
fba2afaa DL |
1379 | /* |
1380 | * Deliver the signal to listening signalfds. This must be called | |
1381 | * with the sighand lock held. | |
1382 | */ | |
1383 | signalfd_notify(p, sig); | |
1da177e4 LT |
1384 | |
1385 | /* | |
1386 | * Put this signal on the shared-pending queue. | |
1387 | * We always use the shared queue for process-wide signals, | |
1388 | * to avoid several races. | |
1389 | */ | |
1da177e4 LT |
1390 | list_add_tail(&q->list, &p->signal->shared_pending.list); |
1391 | sigaddset(&p->signal->shared_pending.signal, sig); | |
1392 | ||
1393 | __group_complete_signal(sig, p); | |
1394 | out: | |
1395 | spin_unlock_irqrestore(&p->sighand->siglock, flags); | |
1396 | read_unlock(&tasklist_lock); | |
e56d0903 | 1397 | return ret; |
1da177e4 LT |
1398 | } |
1399 | ||
1400 | /* | |
1401 | * Wake up any threads in the parent blocked in wait* syscalls. | |
1402 | */ | |
1403 | static inline void __wake_up_parent(struct task_struct *p, | |
1404 | struct task_struct *parent) | |
1405 | { | |
1406 | wake_up_interruptible_sync(&parent->signal->wait_chldexit); | |
1407 | } | |
1408 | ||
1409 | /* | |
1410 | * Let a parent know about the death of a child. | |
1411 | * For a stopped/continued status change, use do_notify_parent_cldstop instead. | |
1412 | */ | |
1413 | ||
1414 | void do_notify_parent(struct task_struct *tsk, int sig) | |
1415 | { | |
1416 | struct siginfo info; | |
1417 | unsigned long flags; | |
1418 | struct sighand_struct *psig; | |
1419 | ||
1420 | BUG_ON(sig == -1); | |
1421 | ||
1422 | /* do_notify_parent_cldstop should have been called instead. */ | |
e1abb39c | 1423 | BUG_ON(task_is_stopped_or_traced(tsk)); |
1da177e4 LT |
1424 | |
1425 | BUG_ON(!tsk->ptrace && | |
1426 | (tsk->group_leader != tsk || !thread_group_empty(tsk))); | |
1427 | ||
1428 | info.si_signo = sig; | |
1429 | info.si_errno = 0; | |
b488893a PE |
1430 | /* |
1431 | * we are under tasklist_lock here so our parent is tied to | |
1432 | * us and cannot exit and release its namespace. | |
1433 | * | |
1434 | * the only it can is to switch its nsproxy with sys_unshare, | |
1435 | * bu uncharing pid namespaces is not allowed, so we'll always | |
1436 | * see relevant namespace | |
1437 | * | |
1438 | * write_lock() currently calls preempt_disable() which is the | |
1439 | * same as rcu_read_lock(), but according to Oleg, this is not | |
1440 | * correct to rely on this | |
1441 | */ | |
1442 | rcu_read_lock(); | |
1443 | info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns); | |
1444 | rcu_read_unlock(); | |
1445 | ||
1da177e4 LT |
1446 | info.si_uid = tsk->uid; |
1447 | ||
1448 | /* FIXME: find out whether or not this is supposed to be c*time. */ | |
1449 | info.si_utime = cputime_to_jiffies(cputime_add(tsk->utime, | |
1450 | tsk->signal->utime)); | |
1451 | info.si_stime = cputime_to_jiffies(cputime_add(tsk->stime, | |
1452 | tsk->signal->stime)); | |
1453 | ||
1454 | info.si_status = tsk->exit_code & 0x7f; | |
1455 | if (tsk->exit_code & 0x80) | |
1456 | info.si_code = CLD_DUMPED; | |
1457 | else if (tsk->exit_code & 0x7f) | |
1458 | info.si_code = CLD_KILLED; | |
1459 | else { | |
1460 | info.si_code = CLD_EXITED; | |
1461 | info.si_status = tsk->exit_code >> 8; | |
1462 | } | |
1463 | ||
1464 | psig = tsk->parent->sighand; | |
1465 | spin_lock_irqsave(&psig->siglock, flags); | |
7ed0175a | 1466 | if (!tsk->ptrace && sig == SIGCHLD && |
1da177e4 LT |
1467 | (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || |
1468 | (psig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT))) { | |
1469 | /* | |
1470 | * We are exiting and our parent doesn't care. POSIX.1 | |
1471 | * defines special semantics for setting SIGCHLD to SIG_IGN | |
1472 | * or setting the SA_NOCLDWAIT flag: we should be reaped | |
1473 | * automatically and not left for our parent's wait4 call. | |
1474 | * Rather than having the parent do it as a magic kind of | |
1475 | * signal handler, we just set this to tell do_exit that we | |
1476 | * can be cleaned up without becoming a zombie. Note that | |
1477 | * we still call __wake_up_parent in this case, because a | |
1478 | * blocked sys_wait4 might now return -ECHILD. | |
1479 | * | |
1480 | * Whether we send SIGCHLD or not for SA_NOCLDWAIT | |
1481 | * is implementation-defined: we do (if you don't want | |
1482 | * it, just use SIG_IGN instead). | |
1483 | */ | |
1484 | tsk->exit_signal = -1; | |
1485 | if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) | |
1486 | sig = 0; | |
1487 | } | |
7ed20e1a | 1488 | if (valid_signal(sig) && sig > 0) |
1da177e4 LT |
1489 | __group_send_sig_info(sig, &info, tsk->parent); |
1490 | __wake_up_parent(tsk, tsk->parent); | |
1491 | spin_unlock_irqrestore(&psig->siglock, flags); | |
1492 | } | |
1493 | ||
a1d5e21e | 1494 | static void do_notify_parent_cldstop(struct task_struct *tsk, int why) |
1da177e4 LT |
1495 | { |
1496 | struct siginfo info; | |
1497 | unsigned long flags; | |
bc505a47 | 1498 | struct task_struct *parent; |
1da177e4 LT |
1499 | struct sighand_struct *sighand; |
1500 | ||
a1d5e21e | 1501 | if (tsk->ptrace & PT_PTRACED) |
bc505a47 ON |
1502 | parent = tsk->parent; |
1503 | else { | |
1504 | tsk = tsk->group_leader; | |
1505 | parent = tsk->real_parent; | |
1506 | } | |
1507 | ||
1da177e4 LT |
1508 | info.si_signo = SIGCHLD; |
1509 | info.si_errno = 0; | |
b488893a PE |
1510 | /* |
1511 | * see comment in do_notify_parent() abot the following 3 lines | |
1512 | */ | |
1513 | rcu_read_lock(); | |
1514 | info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns); | |
1515 | rcu_read_unlock(); | |
1516 | ||
1da177e4 LT |
1517 | info.si_uid = tsk->uid; |
1518 | ||
1519 | /* FIXME: find out whether or not this is supposed to be c*time. */ | |
1520 | info.si_utime = cputime_to_jiffies(tsk->utime); | |
1521 | info.si_stime = cputime_to_jiffies(tsk->stime); | |
1522 | ||
1523 | info.si_code = why; | |
1524 | switch (why) { | |
1525 | case CLD_CONTINUED: | |
1526 | info.si_status = SIGCONT; | |
1527 | break; | |
1528 | case CLD_STOPPED: | |
1529 | info.si_status = tsk->signal->group_exit_code & 0x7f; | |
1530 | break; | |
1531 | case CLD_TRAPPED: | |
1532 | info.si_status = tsk->exit_code & 0x7f; | |
1533 | break; | |
1534 | default: | |
1535 | BUG(); | |
1536 | } | |
1537 | ||
1538 | sighand = parent->sighand; | |
1539 | spin_lock_irqsave(&sighand->siglock, flags); | |
1540 | if (sighand->action[SIGCHLD-1].sa.sa_handler != SIG_IGN && | |
1541 | !(sighand->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) | |
1542 | __group_send_sig_info(SIGCHLD, &info, parent); | |
1543 | /* | |
1544 | * Even if SIGCHLD is not generated, we must wake up wait4 calls. | |
1545 | */ | |
1546 | __wake_up_parent(tsk, parent); | |
1547 | spin_unlock_irqrestore(&sighand->siglock, flags); | |
1548 | } | |
1549 | ||
d5f70c00 ON |
1550 | static inline int may_ptrace_stop(void) |
1551 | { | |
1552 | if (!likely(current->ptrace & PT_PTRACED)) | |
1553 | return 0; | |
d5f70c00 ON |
1554 | /* |
1555 | * Are we in the middle of do_coredump? | |
1556 | * If so and our tracer is also part of the coredump stopping | |
1557 | * is a deadlock situation, and pointless because our tracer | |
1558 | * is dead so don't allow us to stop. | |
1559 | * If SIGKILL was already sent before the caller unlocked | |
1560 | * ->siglock we must see ->core_waiters != 0. Otherwise it | |
1561 | * is safe to enter schedule(). | |
1562 | */ | |
1563 | if (unlikely(current->mm->core_waiters) && | |
1564 | unlikely(current->mm == current->parent->mm)) | |
1565 | return 0; | |
1566 | ||
1567 | return 1; | |
1568 | } | |
1569 | ||
1a669c2f RM |
1570 | /* |
1571 | * Return nonzero if there is a SIGKILL that should be waking us up. | |
1572 | * Called with the siglock held. | |
1573 | */ | |
1574 | static int sigkill_pending(struct task_struct *tsk) | |
1575 | { | |
1576 | return ((sigismember(&tsk->pending.signal, SIGKILL) || | |
1577 | sigismember(&tsk->signal->shared_pending.signal, SIGKILL)) && | |
1578 | !unlikely(sigismember(&tsk->blocked, SIGKILL))); | |
1579 | } | |
1580 | ||
1da177e4 LT |
1581 | /* |
1582 | * This must be called with current->sighand->siglock held. | |
1583 | * | |
1584 | * This should be the path for all ptrace stops. | |
1585 | * We always set current->last_siginfo while stopped here. | |
1586 | * That makes it a way to test a stopped process for | |
1587 | * being ptrace-stopped vs being job-control-stopped. | |
1588 | * | |
20686a30 ON |
1589 | * If we actually decide not to stop at all because the tracer |
1590 | * is gone, we keep current->exit_code unless clear_code. | |
1da177e4 | 1591 | */ |
20686a30 | 1592 | static void ptrace_stop(int exit_code, int clear_code, siginfo_t *info) |
1da177e4 | 1593 | { |
1a669c2f RM |
1594 | int killed = 0; |
1595 | ||
1596 | if (arch_ptrace_stop_needed(exit_code, info)) { | |
1597 | /* | |
1598 | * The arch code has something special to do before a | |
1599 | * ptrace stop. This is allowed to block, e.g. for faults | |
1600 | * on user stack pages. We can't keep the siglock while | |
1601 | * calling arch_ptrace_stop, so we must release it now. | |
1602 | * To preserve proper semantics, we must do this before | |
1603 | * any signal bookkeeping like checking group_stop_count. | |
1604 | * Meanwhile, a SIGKILL could come in before we retake the | |
1605 | * siglock. That must prevent us from sleeping in TASK_TRACED. | |
1606 | * So after regaining the lock, we must check for SIGKILL. | |
1607 | */ | |
1608 | spin_unlock_irq(¤t->sighand->siglock); | |
1609 | arch_ptrace_stop(exit_code, info); | |
1610 | spin_lock_irq(¤t->sighand->siglock); | |
1611 | killed = sigkill_pending(current); | |
1612 | } | |
1613 | ||
1da177e4 LT |
1614 | /* |
1615 | * If there is a group stop in progress, | |
1616 | * we must participate in the bookkeeping. | |
1617 | */ | |
1618 | if (current->signal->group_stop_count > 0) | |
1619 | --current->signal->group_stop_count; | |
1620 | ||
1621 | current->last_siginfo = info; | |
1622 | current->exit_code = exit_code; | |
1623 | ||
1624 | /* Let the debugger run. */ | |
d9ae90ac | 1625 | __set_current_state(TASK_TRACED); |
1da177e4 LT |
1626 | spin_unlock_irq(¤t->sighand->siglock); |
1627 | read_lock(&tasklist_lock); | |
1a669c2f | 1628 | if (!unlikely(killed) && may_ptrace_stop()) { |
a1d5e21e | 1629 | do_notify_parent_cldstop(current, CLD_TRAPPED); |
1da177e4 LT |
1630 | read_unlock(&tasklist_lock); |
1631 | schedule(); | |
1632 | } else { | |
1633 | /* | |
1634 | * By the time we got the lock, our tracer went away. | |
6405f7f4 | 1635 | * Don't drop the lock yet, another tracer may come. |
1da177e4 | 1636 | */ |
6405f7f4 | 1637 | __set_current_state(TASK_RUNNING); |
20686a30 ON |
1638 | if (clear_code) |
1639 | current->exit_code = 0; | |
6405f7f4 | 1640 | read_unlock(&tasklist_lock); |
1da177e4 LT |
1641 | } |
1642 | ||
13b1c3d4 RM |
1643 | /* |
1644 | * While in TASK_TRACED, we were considered "frozen enough". | |
1645 | * Now that we woke up, it's crucial if we're supposed to be | |
1646 | * frozen that we freeze now before running anything substantial. | |
1647 | */ | |
1648 | try_to_freeze(); | |
1649 | ||
1da177e4 LT |
1650 | /* |
1651 | * We are back. Now reacquire the siglock before touching | |
1652 | * last_siginfo, so that we are sure to have synchronized with | |
1653 | * any signal-sending on another CPU that wants to examine it. | |
1654 | */ | |
1655 | spin_lock_irq(¤t->sighand->siglock); | |
1656 | current->last_siginfo = NULL; | |
1657 | ||
1658 | /* | |
1659 | * Queued signals ignored us while we were stopped for tracing. | |
1660 | * So check for any that we should take before resuming user mode. | |
b74d0deb | 1661 | * This sets TIF_SIGPENDING, but never clears it. |
1da177e4 | 1662 | */ |
b74d0deb | 1663 | recalc_sigpending_tsk(current); |
1da177e4 LT |
1664 | } |
1665 | ||
1666 | void ptrace_notify(int exit_code) | |
1667 | { | |
1668 | siginfo_t info; | |
1669 | ||
1670 | BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP); | |
1671 | ||
1672 | memset(&info, 0, sizeof info); | |
1673 | info.si_signo = SIGTRAP; | |
1674 | info.si_code = exit_code; | |
b488893a | 1675 | info.si_pid = task_pid_vnr(current); |
1da177e4 LT |
1676 | info.si_uid = current->uid; |
1677 | ||
1678 | /* Let the debugger run. */ | |
1679 | spin_lock_irq(¤t->sighand->siglock); | |
20686a30 | 1680 | ptrace_stop(exit_code, 1, &info); |
1da177e4 LT |
1681 | spin_unlock_irq(¤t->sighand->siglock); |
1682 | } | |
1683 | ||
1da177e4 LT |
1684 | static void |
1685 | finish_stop(int stop_count) | |
1686 | { | |
1687 | /* | |
1688 | * If there are no other threads in the group, or if there is | |
1689 | * a group stop in progress and we are the last to stop, | |
1690 | * report to the parent. When ptraced, every thread reports itself. | |
1691 | */ | |
a1d5e21e ON |
1692 | if (stop_count == 0 || (current->ptrace & PT_PTRACED)) { |
1693 | read_lock(&tasklist_lock); | |
1694 | do_notify_parent_cldstop(current, CLD_STOPPED); | |
1695 | read_unlock(&tasklist_lock); | |
1696 | } | |
bc505a47 | 1697 | |
3df494a3 RW |
1698 | do { |
1699 | schedule(); | |
1700 | } while (try_to_freeze()); | |
1da177e4 LT |
1701 | /* |
1702 | * Now we don't run again until continued. | |
1703 | */ | |
1704 | current->exit_code = 0; | |
1705 | } | |
1706 | ||
1707 | /* | |
1708 | * This performs the stopping for SIGSTOP and other stop signals. | |
1709 | * We have to stop all threads in the thread group. | |
1710 | * Returns nonzero if we've actually stopped and released the siglock. | |
1711 | * Returns zero if we didn't stop and still hold the siglock. | |
1712 | */ | |
a122b341 | 1713 | static int do_signal_stop(int signr) |
1da177e4 LT |
1714 | { |
1715 | struct signal_struct *sig = current->signal; | |
dac27f4a | 1716 | int stop_count; |
1da177e4 | 1717 | |
1da177e4 LT |
1718 | if (sig->group_stop_count > 0) { |
1719 | /* | |
1720 | * There is a group stop in progress. We don't need to | |
1721 | * start another one. | |
1722 | */ | |
1da177e4 | 1723 | stop_count = --sig->group_stop_count; |
dac27f4a | 1724 | } else { |
f558b7e4 ON |
1725 | struct task_struct *t; |
1726 | ||
ed5d2cac ON |
1727 | if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED) || |
1728 | unlikely(sig->group_exit_task)) | |
f558b7e4 | 1729 | return 0; |
1da177e4 LT |
1730 | /* |
1731 | * There is no group stop already in progress. | |
a122b341 | 1732 | * We must initiate one now. |
1da177e4 | 1733 | */ |
a122b341 | 1734 | sig->group_exit_code = signr; |
1da177e4 | 1735 | |
a122b341 ON |
1736 | stop_count = 0; |
1737 | for (t = next_thread(current); t != current; t = next_thread(t)) | |
1da177e4 | 1738 | /* |
a122b341 ON |
1739 | * Setting state to TASK_STOPPED for a group |
1740 | * stop is always done with the siglock held, | |
1741 | * so this check has no races. | |
1da177e4 | 1742 | */ |
d12619b5 | 1743 | if (!(t->flags & PF_EXITING) && |
e1abb39c | 1744 | !task_is_stopped_or_traced(t)) { |
a122b341 ON |
1745 | stop_count++; |
1746 | signal_wake_up(t, 0); | |
1747 | } | |
1748 | sig->group_stop_count = stop_count; | |
1da177e4 LT |
1749 | } |
1750 | ||
dac27f4a ON |
1751 | if (stop_count == 0) |
1752 | sig->flags = SIGNAL_STOP_STOPPED; | |
1753 | current->exit_code = sig->group_exit_code; | |
1754 | __set_current_state(TASK_STOPPED); | |
1755 | ||
1756 | spin_unlock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
1757 | finish_stop(stop_count); |
1758 | return 1; | |
1759 | } | |
1760 | ||
18c98b65 RM |
1761 | static int ptrace_signal(int signr, siginfo_t *info, |
1762 | struct pt_regs *regs, void *cookie) | |
1763 | { | |
1764 | if (!(current->ptrace & PT_PTRACED)) | |
1765 | return signr; | |
1766 | ||
1767 | ptrace_signal_deliver(regs, cookie); | |
1768 | ||
1769 | /* Let the debugger run. */ | |
1770 | ptrace_stop(signr, 0, info); | |
1771 | ||
1772 | /* We're back. Did the debugger cancel the sig? */ | |
1773 | signr = current->exit_code; | |
1774 | if (signr == 0) | |
1775 | return signr; | |
1776 | ||
1777 | current->exit_code = 0; | |
1778 | ||
1779 | /* Update the siginfo structure if the signal has | |
1780 | changed. If the debugger wanted something | |
1781 | specific in the siginfo structure then it should | |
1782 | have updated *info via PTRACE_SETSIGINFO. */ | |
1783 | if (signr != info->si_signo) { | |
1784 | info->si_signo = signr; | |
1785 | info->si_errno = 0; | |
1786 | info->si_code = SI_USER; | |
1787 | info->si_pid = task_pid_vnr(current->parent); | |
1788 | info->si_uid = current->parent->uid; | |
1789 | } | |
1790 | ||
1791 | /* If the (new) signal is now blocked, requeue it. */ | |
1792 | if (sigismember(¤t->blocked, signr)) { | |
1793 | specific_send_sig_info(signr, info, current); | |
1794 | signr = 0; | |
1795 | } | |
1796 | ||
1797 | return signr; | |
1798 | } | |
1799 | ||
1da177e4 LT |
1800 | int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka, |
1801 | struct pt_regs *regs, void *cookie) | |
1802 | { | |
1803 | sigset_t *mask = ¤t->blocked; | |
1804 | int signr = 0; | |
1805 | ||
13b1c3d4 RM |
1806 | relock: |
1807 | /* | |
1808 | * We'll jump back here after any time we were stopped in TASK_STOPPED. | |
1809 | * While in TASK_STOPPED, we were considered "frozen enough". | |
1810 | * Now that we woke up, it's crucial if we're supposed to be | |
1811 | * frozen that we freeze now before running anything substantial. | |
1812 | */ | |
fc558a74 RW |
1813 | try_to_freeze(); |
1814 | ||
1da177e4 LT |
1815 | spin_lock_irq(¤t->sighand->siglock); |
1816 | for (;;) { | |
1817 | struct k_sigaction *ka; | |
1818 | ||
1819 | if (unlikely(current->signal->group_stop_count > 0) && | |
f558b7e4 | 1820 | do_signal_stop(0)) |
1da177e4 LT |
1821 | goto relock; |
1822 | ||
1823 | signr = dequeue_signal(current, mask, info); | |
1824 | ||
1825 | if (!signr) | |
1826 | break; /* will return 0 */ | |
1827 | ||
18c98b65 RM |
1828 | if (signr != SIGKILL) { |
1829 | signr = ptrace_signal(signr, info, regs, cookie); | |
1830 | if (!signr) | |
1da177e4 | 1831 | continue; |
1da177e4 LT |
1832 | } |
1833 | ||
1834 | ka = ¤t->sighand->action[signr-1]; | |
1835 | if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */ | |
1836 | continue; | |
1837 | if (ka->sa.sa_handler != SIG_DFL) { | |
1838 | /* Run the handler. */ | |
1839 | *return_ka = *ka; | |
1840 | ||
1841 | if (ka->sa.sa_flags & SA_ONESHOT) | |
1842 | ka->sa.sa_handler = SIG_DFL; | |
1843 | ||
1844 | break; /* will return non-zero "signr" value */ | |
1845 | } | |
1846 | ||
1847 | /* | |
1848 | * Now we are doing the default action for this signal. | |
1849 | */ | |
1850 | if (sig_kernel_ignore(signr)) /* Default is nothing. */ | |
1851 | continue; | |
1852 | ||
84d73786 | 1853 | /* |
0fbc26a6 | 1854 | * Global init gets no signals it doesn't want. |
84d73786 | 1855 | */ |
0fbc26a6 | 1856 | if (is_global_init(current)) |
1da177e4 LT |
1857 | continue; |
1858 | ||
1859 | if (sig_kernel_stop(signr)) { | |
1860 | /* | |
1861 | * The default action is to stop all threads in | |
1862 | * the thread group. The job control signals | |
1863 | * do nothing in an orphaned pgrp, but SIGSTOP | |
1864 | * always works. Note that siglock needs to be | |
1865 | * dropped during the call to is_orphaned_pgrp() | |
1866 | * because of lock ordering with tasklist_lock. | |
1867 | * This allows an intervening SIGCONT to be posted. | |
1868 | * We need to check for that and bail out if necessary. | |
1869 | */ | |
1870 | if (signr != SIGSTOP) { | |
1871 | spin_unlock_irq(¤t->sighand->siglock); | |
1872 | ||
1873 | /* signals can be posted during this window */ | |
1874 | ||
3e7cd6c4 | 1875 | if (is_current_pgrp_orphaned()) |
1da177e4 LT |
1876 | goto relock; |
1877 | ||
1878 | spin_lock_irq(¤t->sighand->siglock); | |
1879 | } | |
1880 | ||
1881 | if (likely(do_signal_stop(signr))) { | |
1882 | /* It released the siglock. */ | |
1883 | goto relock; | |
1884 | } | |
1885 | ||
1886 | /* | |
1887 | * We didn't actually stop, due to a race | |
1888 | * with SIGCONT or something like that. | |
1889 | */ | |
1890 | continue; | |
1891 | } | |
1892 | ||
1893 | spin_unlock_irq(¤t->sighand->siglock); | |
1894 | ||
1895 | /* | |
1896 | * Anything else is fatal, maybe with a core dump. | |
1897 | */ | |
1898 | current->flags |= PF_SIGNALED; | |
45807a1d IM |
1899 | if ((signr != SIGKILL) && print_fatal_signals) |
1900 | print_fatal_signal(regs, signr); | |
1da177e4 LT |
1901 | if (sig_kernel_coredump(signr)) { |
1902 | /* | |
1903 | * If it was able to dump core, this kills all | |
1904 | * other threads in the group and synchronizes with | |
1905 | * their demise. If we lost the race with another | |
1906 | * thread getting here, it set group_exit_code | |
1907 | * first and our do_group_exit call below will use | |
1908 | * that value and ignore the one we pass it. | |
1909 | */ | |
1910 | do_coredump((long)signr, signr, regs); | |
1911 | } | |
1912 | ||
1913 | /* | |
1914 | * Death signals, no core dump. | |
1915 | */ | |
1916 | do_group_exit(signr); | |
1917 | /* NOTREACHED */ | |
1918 | } | |
1919 | spin_unlock_irq(¤t->sighand->siglock); | |
1920 | return signr; | |
1921 | } | |
1922 | ||
d12619b5 ON |
1923 | void exit_signals(struct task_struct *tsk) |
1924 | { | |
1925 | int group_stop = 0; | |
5dee1707 | 1926 | struct task_struct *t; |
d12619b5 | 1927 | |
5dee1707 ON |
1928 | if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) { |
1929 | tsk->flags |= PF_EXITING; | |
1930 | return; | |
d12619b5 ON |
1931 | } |
1932 | ||
5dee1707 | 1933 | spin_lock_irq(&tsk->sighand->siglock); |
d12619b5 ON |
1934 | /* |
1935 | * From now this task is not visible for group-wide signals, | |
1936 | * see wants_signal(), do_signal_stop(). | |
1937 | */ | |
1938 | tsk->flags |= PF_EXITING; | |
5dee1707 ON |
1939 | if (!signal_pending(tsk)) |
1940 | goto out; | |
1941 | ||
1942 | /* It could be that __group_complete_signal() choose us to | |
1943 | * notify about group-wide signal. Another thread should be | |
1944 | * woken now to take the signal since we will not. | |
1945 | */ | |
1946 | for (t = tsk; (t = next_thread(t)) != tsk; ) | |
1947 | if (!signal_pending(t) && !(t->flags & PF_EXITING)) | |
1948 | recalc_sigpending_and_wake(t); | |
1949 | ||
1950 | if (unlikely(tsk->signal->group_stop_count) && | |
1951 | !--tsk->signal->group_stop_count) { | |
1952 | tsk->signal->flags = SIGNAL_STOP_STOPPED; | |
1953 | group_stop = 1; | |
1954 | } | |
1955 | out: | |
d12619b5 ON |
1956 | spin_unlock_irq(&tsk->sighand->siglock); |
1957 | ||
1958 | if (unlikely(group_stop)) { | |
1959 | read_lock(&tasklist_lock); | |
1960 | do_notify_parent_cldstop(tsk, CLD_STOPPED); | |
1961 | read_unlock(&tasklist_lock); | |
1962 | } | |
1963 | } | |
1964 | ||
1da177e4 LT |
1965 | EXPORT_SYMBOL(recalc_sigpending); |
1966 | EXPORT_SYMBOL_GPL(dequeue_signal); | |
1967 | EXPORT_SYMBOL(flush_signals); | |
1968 | EXPORT_SYMBOL(force_sig); | |
1da177e4 LT |
1969 | EXPORT_SYMBOL(kill_proc); |
1970 | EXPORT_SYMBOL(ptrace_notify); | |
1971 | EXPORT_SYMBOL(send_sig); | |
1972 | EXPORT_SYMBOL(send_sig_info); | |
1973 | EXPORT_SYMBOL(sigprocmask); | |
1974 | EXPORT_SYMBOL(block_all_signals); | |
1975 | EXPORT_SYMBOL(unblock_all_signals); | |
1976 | ||
1977 | ||
1978 | /* | |
1979 | * System call entry points. | |
1980 | */ | |
1981 | ||
1982 | asmlinkage long sys_restart_syscall(void) | |
1983 | { | |
1984 | struct restart_block *restart = ¤t_thread_info()->restart_block; | |
1985 | return restart->fn(restart); | |
1986 | } | |
1987 | ||
1988 | long do_no_restart_syscall(struct restart_block *param) | |
1989 | { | |
1990 | return -EINTR; | |
1991 | } | |
1992 | ||
1993 | /* | |
1994 | * We don't need to get the kernel lock - this is all local to this | |
1995 | * particular thread.. (and that's good, because this is _heavily_ | |
1996 | * used by various programs) | |
1997 | */ | |
1998 | ||
1999 | /* | |
2000 | * This is also useful for kernel threads that want to temporarily | |
2001 | * (or permanently) block certain signals. | |
2002 | * | |
2003 | * NOTE! Unlike the user-mode sys_sigprocmask(), the kernel | |
2004 | * interface happily blocks "unblockable" signals like SIGKILL | |
2005 | * and friends. | |
2006 | */ | |
2007 | int sigprocmask(int how, sigset_t *set, sigset_t *oldset) | |
2008 | { | |
2009 | int error; | |
1da177e4 LT |
2010 | |
2011 | spin_lock_irq(¤t->sighand->siglock); | |
a26fd335 ON |
2012 | if (oldset) |
2013 | *oldset = current->blocked; | |
2014 | ||
1da177e4 LT |
2015 | error = 0; |
2016 | switch (how) { | |
2017 | case SIG_BLOCK: | |
2018 | sigorsets(¤t->blocked, ¤t->blocked, set); | |
2019 | break; | |
2020 | case SIG_UNBLOCK: | |
2021 | signandsets(¤t->blocked, ¤t->blocked, set); | |
2022 | break; | |
2023 | case SIG_SETMASK: | |
2024 | current->blocked = *set; | |
2025 | break; | |
2026 | default: | |
2027 | error = -EINVAL; | |
2028 | } | |
2029 | recalc_sigpending(); | |
2030 | spin_unlock_irq(¤t->sighand->siglock); | |
a26fd335 | 2031 | |
1da177e4 LT |
2032 | return error; |
2033 | } | |
2034 | ||
2035 | asmlinkage long | |
2036 | sys_rt_sigprocmask(int how, sigset_t __user *set, sigset_t __user *oset, size_t sigsetsize) | |
2037 | { | |
2038 | int error = -EINVAL; | |
2039 | sigset_t old_set, new_set; | |
2040 | ||
2041 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2042 | if (sigsetsize != sizeof(sigset_t)) | |
2043 | goto out; | |
2044 | ||
2045 | if (set) { | |
2046 | error = -EFAULT; | |
2047 | if (copy_from_user(&new_set, set, sizeof(*set))) | |
2048 | goto out; | |
2049 | sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2050 | ||
2051 | error = sigprocmask(how, &new_set, &old_set); | |
2052 | if (error) | |
2053 | goto out; | |
2054 | if (oset) | |
2055 | goto set_old; | |
2056 | } else if (oset) { | |
2057 | spin_lock_irq(¤t->sighand->siglock); | |
2058 | old_set = current->blocked; | |
2059 | spin_unlock_irq(¤t->sighand->siglock); | |
2060 | ||
2061 | set_old: | |
2062 | error = -EFAULT; | |
2063 | if (copy_to_user(oset, &old_set, sizeof(*oset))) | |
2064 | goto out; | |
2065 | } | |
2066 | error = 0; | |
2067 | out: | |
2068 | return error; | |
2069 | } | |
2070 | ||
2071 | long do_sigpending(void __user *set, unsigned long sigsetsize) | |
2072 | { | |
2073 | long error = -EINVAL; | |
2074 | sigset_t pending; | |
2075 | ||
2076 | if (sigsetsize > sizeof(sigset_t)) | |
2077 | goto out; | |
2078 | ||
2079 | spin_lock_irq(¤t->sighand->siglock); | |
2080 | sigorsets(&pending, ¤t->pending.signal, | |
2081 | ¤t->signal->shared_pending.signal); | |
2082 | spin_unlock_irq(¤t->sighand->siglock); | |
2083 | ||
2084 | /* Outside the lock because only this thread touches it. */ | |
2085 | sigandsets(&pending, ¤t->blocked, &pending); | |
2086 | ||
2087 | error = -EFAULT; | |
2088 | if (!copy_to_user(set, &pending, sigsetsize)) | |
2089 | error = 0; | |
2090 | ||
2091 | out: | |
2092 | return error; | |
2093 | } | |
2094 | ||
2095 | asmlinkage long | |
2096 | sys_rt_sigpending(sigset_t __user *set, size_t sigsetsize) | |
2097 | { | |
2098 | return do_sigpending(set, sigsetsize); | |
2099 | } | |
2100 | ||
2101 | #ifndef HAVE_ARCH_COPY_SIGINFO_TO_USER | |
2102 | ||
2103 | int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from) | |
2104 | { | |
2105 | int err; | |
2106 | ||
2107 | if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) | |
2108 | return -EFAULT; | |
2109 | if (from->si_code < 0) | |
2110 | return __copy_to_user(to, from, sizeof(siginfo_t)) | |
2111 | ? -EFAULT : 0; | |
2112 | /* | |
2113 | * If you change siginfo_t structure, please be sure | |
2114 | * this code is fixed accordingly. | |
fba2afaa DL |
2115 | * Please remember to update the signalfd_copyinfo() function |
2116 | * inside fs/signalfd.c too, in case siginfo_t changes. | |
1da177e4 LT |
2117 | * It should never copy any pad contained in the structure |
2118 | * to avoid security leaks, but must copy the generic | |
2119 | * 3 ints plus the relevant union member. | |
2120 | */ | |
2121 | err = __put_user(from->si_signo, &to->si_signo); | |
2122 | err |= __put_user(from->si_errno, &to->si_errno); | |
2123 | err |= __put_user((short)from->si_code, &to->si_code); | |
2124 | switch (from->si_code & __SI_MASK) { | |
2125 | case __SI_KILL: | |
2126 | err |= __put_user(from->si_pid, &to->si_pid); | |
2127 | err |= __put_user(from->si_uid, &to->si_uid); | |
2128 | break; | |
2129 | case __SI_TIMER: | |
2130 | err |= __put_user(from->si_tid, &to->si_tid); | |
2131 | err |= __put_user(from->si_overrun, &to->si_overrun); | |
2132 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2133 | break; | |
2134 | case __SI_POLL: | |
2135 | err |= __put_user(from->si_band, &to->si_band); | |
2136 | err |= __put_user(from->si_fd, &to->si_fd); | |
2137 | break; | |
2138 | case __SI_FAULT: | |
2139 | err |= __put_user(from->si_addr, &to->si_addr); | |
2140 | #ifdef __ARCH_SI_TRAPNO | |
2141 | err |= __put_user(from->si_trapno, &to->si_trapno); | |
2142 | #endif | |
2143 | break; | |
2144 | case __SI_CHLD: | |
2145 | err |= __put_user(from->si_pid, &to->si_pid); | |
2146 | err |= __put_user(from->si_uid, &to->si_uid); | |
2147 | err |= __put_user(from->si_status, &to->si_status); | |
2148 | err |= __put_user(from->si_utime, &to->si_utime); | |
2149 | err |= __put_user(from->si_stime, &to->si_stime); | |
2150 | break; | |
2151 | case __SI_RT: /* This is not generated by the kernel as of now. */ | |
2152 | case __SI_MESGQ: /* But this is */ | |
2153 | err |= __put_user(from->si_pid, &to->si_pid); | |
2154 | err |= __put_user(from->si_uid, &to->si_uid); | |
2155 | err |= __put_user(from->si_ptr, &to->si_ptr); | |
2156 | break; | |
2157 | default: /* this is just in case for now ... */ | |
2158 | err |= __put_user(from->si_pid, &to->si_pid); | |
2159 | err |= __put_user(from->si_uid, &to->si_uid); | |
2160 | break; | |
2161 | } | |
2162 | return err; | |
2163 | } | |
2164 | ||
2165 | #endif | |
2166 | ||
2167 | asmlinkage long | |
2168 | sys_rt_sigtimedwait(const sigset_t __user *uthese, | |
2169 | siginfo_t __user *uinfo, | |
2170 | const struct timespec __user *uts, | |
2171 | size_t sigsetsize) | |
2172 | { | |
2173 | int ret, sig; | |
2174 | sigset_t these; | |
2175 | struct timespec ts; | |
2176 | siginfo_t info; | |
2177 | long timeout = 0; | |
2178 | ||
2179 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2180 | if (sigsetsize != sizeof(sigset_t)) | |
2181 | return -EINVAL; | |
2182 | ||
2183 | if (copy_from_user(&these, uthese, sizeof(these))) | |
2184 | return -EFAULT; | |
2185 | ||
2186 | /* | |
2187 | * Invert the set of allowed signals to get those we | |
2188 | * want to block. | |
2189 | */ | |
2190 | sigdelsetmask(&these, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2191 | signotset(&these); | |
2192 | ||
2193 | if (uts) { | |
2194 | if (copy_from_user(&ts, uts, sizeof(ts))) | |
2195 | return -EFAULT; | |
2196 | if (ts.tv_nsec >= 1000000000L || ts.tv_nsec < 0 | |
2197 | || ts.tv_sec < 0) | |
2198 | return -EINVAL; | |
2199 | } | |
2200 | ||
2201 | spin_lock_irq(¤t->sighand->siglock); | |
2202 | sig = dequeue_signal(current, &these, &info); | |
2203 | if (!sig) { | |
2204 | timeout = MAX_SCHEDULE_TIMEOUT; | |
2205 | if (uts) | |
2206 | timeout = (timespec_to_jiffies(&ts) | |
2207 | + (ts.tv_sec || ts.tv_nsec)); | |
2208 | ||
2209 | if (timeout) { | |
2210 | /* None ready -- temporarily unblock those we're | |
2211 | * interested while we are sleeping in so that we'll | |
2212 | * be awakened when they arrive. */ | |
2213 | current->real_blocked = current->blocked; | |
2214 | sigandsets(¤t->blocked, ¤t->blocked, &these); | |
2215 | recalc_sigpending(); | |
2216 | spin_unlock_irq(¤t->sighand->siglock); | |
2217 | ||
75bcc8c5 | 2218 | timeout = schedule_timeout_interruptible(timeout); |
1da177e4 | 2219 | |
1da177e4 LT |
2220 | spin_lock_irq(¤t->sighand->siglock); |
2221 | sig = dequeue_signal(current, &these, &info); | |
2222 | current->blocked = current->real_blocked; | |
2223 | siginitset(¤t->real_blocked, 0); | |
2224 | recalc_sigpending(); | |
2225 | } | |
2226 | } | |
2227 | spin_unlock_irq(¤t->sighand->siglock); | |
2228 | ||
2229 | if (sig) { | |
2230 | ret = sig; | |
2231 | if (uinfo) { | |
2232 | if (copy_siginfo_to_user(uinfo, &info)) | |
2233 | ret = -EFAULT; | |
2234 | } | |
2235 | } else { | |
2236 | ret = -EAGAIN; | |
2237 | if (timeout) | |
2238 | ret = -EINTR; | |
2239 | } | |
2240 | ||
2241 | return ret; | |
2242 | } | |
2243 | ||
2244 | asmlinkage long | |
2245 | sys_kill(int pid, int sig) | |
2246 | { | |
2247 | struct siginfo info; | |
2248 | ||
2249 | info.si_signo = sig; | |
2250 | info.si_errno = 0; | |
2251 | info.si_code = SI_USER; | |
b488893a | 2252 | info.si_pid = task_tgid_vnr(current); |
1da177e4 LT |
2253 | info.si_uid = current->uid; |
2254 | ||
2255 | return kill_something_info(sig, &info, pid); | |
2256 | } | |
2257 | ||
6dd69f10 | 2258 | static int do_tkill(int tgid, int pid, int sig) |
1da177e4 | 2259 | { |
1da177e4 | 2260 | int error; |
6dd69f10 | 2261 | struct siginfo info; |
1da177e4 LT |
2262 | struct task_struct *p; |
2263 | ||
6dd69f10 | 2264 | error = -ESRCH; |
1da177e4 LT |
2265 | info.si_signo = sig; |
2266 | info.si_errno = 0; | |
2267 | info.si_code = SI_TKILL; | |
b488893a | 2268 | info.si_pid = task_tgid_vnr(current); |
1da177e4 LT |
2269 | info.si_uid = current->uid; |
2270 | ||
2271 | read_lock(&tasklist_lock); | |
228ebcbe | 2272 | p = find_task_by_vpid(pid); |
b488893a | 2273 | if (p && (tgid <= 0 || task_tgid_vnr(p) == tgid)) { |
1da177e4 LT |
2274 | error = check_kill_permission(sig, &info, p); |
2275 | /* | |
2276 | * The null signal is a permissions and process existence | |
2277 | * probe. No signal is actually delivered. | |
2278 | */ | |
2279 | if (!error && sig && p->sighand) { | |
2280 | spin_lock_irq(&p->sighand->siglock); | |
2281 | handle_stop_signal(sig, p); | |
2282 | error = specific_send_sig_info(sig, &info, p); | |
2283 | spin_unlock_irq(&p->sighand->siglock); | |
2284 | } | |
2285 | } | |
2286 | read_unlock(&tasklist_lock); | |
6dd69f10 | 2287 | |
1da177e4 LT |
2288 | return error; |
2289 | } | |
2290 | ||
6dd69f10 VL |
2291 | /** |
2292 | * sys_tgkill - send signal to one specific thread | |
2293 | * @tgid: the thread group ID of the thread | |
2294 | * @pid: the PID of the thread | |
2295 | * @sig: signal to be sent | |
2296 | * | |
72fd4a35 | 2297 | * This syscall also checks the @tgid and returns -ESRCH even if the PID |
6dd69f10 VL |
2298 | * exists but it's not belonging to the target process anymore. This |
2299 | * method solves the problem of threads exiting and PIDs getting reused. | |
2300 | */ | |
2301 | asmlinkage long sys_tgkill(int tgid, int pid, int sig) | |
2302 | { | |
2303 | /* This is only valid for single tasks */ | |
2304 | if (pid <= 0 || tgid <= 0) | |
2305 | return -EINVAL; | |
2306 | ||
2307 | return do_tkill(tgid, pid, sig); | |
2308 | } | |
2309 | ||
1da177e4 LT |
2310 | /* |
2311 | * Send a signal to only one task, even if it's a CLONE_THREAD task. | |
2312 | */ | |
2313 | asmlinkage long | |
2314 | sys_tkill(int pid, int sig) | |
2315 | { | |
1da177e4 LT |
2316 | /* This is only valid for single tasks */ |
2317 | if (pid <= 0) | |
2318 | return -EINVAL; | |
2319 | ||
6dd69f10 | 2320 | return do_tkill(0, pid, sig); |
1da177e4 LT |
2321 | } |
2322 | ||
2323 | asmlinkage long | |
2324 | sys_rt_sigqueueinfo(int pid, int sig, siginfo_t __user *uinfo) | |
2325 | { | |
2326 | siginfo_t info; | |
2327 | ||
2328 | if (copy_from_user(&info, uinfo, sizeof(siginfo_t))) | |
2329 | return -EFAULT; | |
2330 | ||
2331 | /* Not even root can pretend to send signals from the kernel. | |
2332 | Nor can they impersonate a kill(), which adds source info. */ | |
2333 | if (info.si_code >= 0) | |
2334 | return -EPERM; | |
2335 | info.si_signo = sig; | |
2336 | ||
2337 | /* POSIX.1b doesn't mention process groups. */ | |
2338 | return kill_proc_info(sig, &info, pid); | |
2339 | } | |
2340 | ||
88531f72 | 2341 | int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact) |
1da177e4 LT |
2342 | { |
2343 | struct k_sigaction *k; | |
71fabd5e | 2344 | sigset_t mask; |
1da177e4 | 2345 | |
7ed20e1a | 2346 | if (!valid_signal(sig) || sig < 1 || (act && sig_kernel_only(sig))) |
1da177e4 LT |
2347 | return -EINVAL; |
2348 | ||
2349 | k = ¤t->sighand->action[sig-1]; | |
2350 | ||
2351 | spin_lock_irq(¤t->sighand->siglock); | |
1da177e4 LT |
2352 | if (oact) |
2353 | *oact = *k; | |
2354 | ||
2355 | if (act) { | |
9ac95f2f ON |
2356 | sigdelsetmask(&act->sa.sa_mask, |
2357 | sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
88531f72 | 2358 | *k = *act; |
1da177e4 LT |
2359 | /* |
2360 | * POSIX 3.3.1.3: | |
2361 | * "Setting a signal action to SIG_IGN for a signal that is | |
2362 | * pending shall cause the pending signal to be discarded, | |
2363 | * whether or not it is blocked." | |
2364 | * | |
2365 | * "Setting a signal action to SIG_DFL for a signal that is | |
2366 | * pending and whose default action is to ignore the signal | |
2367 | * (for example, SIGCHLD), shall cause the pending signal to | |
2368 | * be discarded, whether or not it is blocked" | |
2369 | */ | |
2370 | if (act->sa.sa_handler == SIG_IGN || | |
88531f72 | 2371 | (act->sa.sa_handler == SIG_DFL && sig_kernel_ignore(sig))) { |
1da177e4 | 2372 | struct task_struct *t = current; |
71fabd5e GA |
2373 | sigemptyset(&mask); |
2374 | sigaddset(&mask, sig); | |
2375 | rm_from_queue_full(&mask, &t->signal->shared_pending); | |
1da177e4 | 2376 | do { |
71fabd5e | 2377 | rm_from_queue_full(&mask, &t->pending); |
1da177e4 LT |
2378 | t = next_thread(t); |
2379 | } while (t != current); | |
1da177e4 | 2380 | } |
1da177e4 LT |
2381 | } |
2382 | ||
2383 | spin_unlock_irq(¤t->sighand->siglock); | |
2384 | return 0; | |
2385 | } | |
2386 | ||
2387 | int | |
2388 | do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long sp) | |
2389 | { | |
2390 | stack_t oss; | |
2391 | int error; | |
2392 | ||
2393 | if (uoss) { | |
2394 | oss.ss_sp = (void __user *) current->sas_ss_sp; | |
2395 | oss.ss_size = current->sas_ss_size; | |
2396 | oss.ss_flags = sas_ss_flags(sp); | |
2397 | } | |
2398 | ||
2399 | if (uss) { | |
2400 | void __user *ss_sp; | |
2401 | size_t ss_size; | |
2402 | int ss_flags; | |
2403 | ||
2404 | error = -EFAULT; | |
2405 | if (!access_ok(VERIFY_READ, uss, sizeof(*uss)) | |
2406 | || __get_user(ss_sp, &uss->ss_sp) | |
2407 | || __get_user(ss_flags, &uss->ss_flags) | |
2408 | || __get_user(ss_size, &uss->ss_size)) | |
2409 | goto out; | |
2410 | ||
2411 | error = -EPERM; | |
2412 | if (on_sig_stack(sp)) | |
2413 | goto out; | |
2414 | ||
2415 | error = -EINVAL; | |
2416 | /* | |
2417 | * | |
2418 | * Note - this code used to test ss_flags incorrectly | |
2419 | * old code may have been written using ss_flags==0 | |
2420 | * to mean ss_flags==SS_ONSTACK (as this was the only | |
2421 | * way that worked) - this fix preserves that older | |
2422 | * mechanism | |
2423 | */ | |
2424 | if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0) | |
2425 | goto out; | |
2426 | ||
2427 | if (ss_flags == SS_DISABLE) { | |
2428 | ss_size = 0; | |
2429 | ss_sp = NULL; | |
2430 | } else { | |
2431 | error = -ENOMEM; | |
2432 | if (ss_size < MINSIGSTKSZ) | |
2433 | goto out; | |
2434 | } | |
2435 | ||
2436 | current->sas_ss_sp = (unsigned long) ss_sp; | |
2437 | current->sas_ss_size = ss_size; | |
2438 | } | |
2439 | ||
2440 | if (uoss) { | |
2441 | error = -EFAULT; | |
2442 | if (copy_to_user(uoss, &oss, sizeof(oss))) | |
2443 | goto out; | |
2444 | } | |
2445 | ||
2446 | error = 0; | |
2447 | out: | |
2448 | return error; | |
2449 | } | |
2450 | ||
2451 | #ifdef __ARCH_WANT_SYS_SIGPENDING | |
2452 | ||
2453 | asmlinkage long | |
2454 | sys_sigpending(old_sigset_t __user *set) | |
2455 | { | |
2456 | return do_sigpending(set, sizeof(*set)); | |
2457 | } | |
2458 | ||
2459 | #endif | |
2460 | ||
2461 | #ifdef __ARCH_WANT_SYS_SIGPROCMASK | |
2462 | /* Some platforms have their own version with special arguments others | |
2463 | support only sys_rt_sigprocmask. */ | |
2464 | ||
2465 | asmlinkage long | |
2466 | sys_sigprocmask(int how, old_sigset_t __user *set, old_sigset_t __user *oset) | |
2467 | { | |
2468 | int error; | |
2469 | old_sigset_t old_set, new_set; | |
2470 | ||
2471 | if (set) { | |
2472 | error = -EFAULT; | |
2473 | if (copy_from_user(&new_set, set, sizeof(*set))) | |
2474 | goto out; | |
2475 | new_set &= ~(sigmask(SIGKILL) | sigmask(SIGSTOP)); | |
2476 | ||
2477 | spin_lock_irq(¤t->sighand->siglock); | |
2478 | old_set = current->blocked.sig[0]; | |
2479 | ||
2480 | error = 0; | |
2481 | switch (how) { | |
2482 | default: | |
2483 | error = -EINVAL; | |
2484 | break; | |
2485 | case SIG_BLOCK: | |
2486 | sigaddsetmask(¤t->blocked, new_set); | |
2487 | break; | |
2488 | case SIG_UNBLOCK: | |
2489 | sigdelsetmask(¤t->blocked, new_set); | |
2490 | break; | |
2491 | case SIG_SETMASK: | |
2492 | current->blocked.sig[0] = new_set; | |
2493 | break; | |
2494 | } | |
2495 | ||
2496 | recalc_sigpending(); | |
2497 | spin_unlock_irq(¤t->sighand->siglock); | |
2498 | if (error) | |
2499 | goto out; | |
2500 | if (oset) | |
2501 | goto set_old; | |
2502 | } else if (oset) { | |
2503 | old_set = current->blocked.sig[0]; | |
2504 | set_old: | |
2505 | error = -EFAULT; | |
2506 | if (copy_to_user(oset, &old_set, sizeof(*oset))) | |
2507 | goto out; | |
2508 | } | |
2509 | error = 0; | |
2510 | out: | |
2511 | return error; | |
2512 | } | |
2513 | #endif /* __ARCH_WANT_SYS_SIGPROCMASK */ | |
2514 | ||
2515 | #ifdef __ARCH_WANT_SYS_RT_SIGACTION | |
2516 | asmlinkage long | |
2517 | sys_rt_sigaction(int sig, | |
2518 | const struct sigaction __user *act, | |
2519 | struct sigaction __user *oact, | |
2520 | size_t sigsetsize) | |
2521 | { | |
2522 | struct k_sigaction new_sa, old_sa; | |
2523 | int ret = -EINVAL; | |
2524 | ||
2525 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2526 | if (sigsetsize != sizeof(sigset_t)) | |
2527 | goto out; | |
2528 | ||
2529 | if (act) { | |
2530 | if (copy_from_user(&new_sa.sa, act, sizeof(new_sa.sa))) | |
2531 | return -EFAULT; | |
2532 | } | |
2533 | ||
2534 | ret = do_sigaction(sig, act ? &new_sa : NULL, oact ? &old_sa : NULL); | |
2535 | ||
2536 | if (!ret && oact) { | |
2537 | if (copy_to_user(oact, &old_sa.sa, sizeof(old_sa.sa))) | |
2538 | return -EFAULT; | |
2539 | } | |
2540 | out: | |
2541 | return ret; | |
2542 | } | |
2543 | #endif /* __ARCH_WANT_SYS_RT_SIGACTION */ | |
2544 | ||
2545 | #ifdef __ARCH_WANT_SYS_SGETMASK | |
2546 | ||
2547 | /* | |
2548 | * For backwards compatibility. Functionality superseded by sigprocmask. | |
2549 | */ | |
2550 | asmlinkage long | |
2551 | sys_sgetmask(void) | |
2552 | { | |
2553 | /* SMP safe */ | |
2554 | return current->blocked.sig[0]; | |
2555 | } | |
2556 | ||
2557 | asmlinkage long | |
2558 | sys_ssetmask(int newmask) | |
2559 | { | |
2560 | int old; | |
2561 | ||
2562 | spin_lock_irq(¤t->sighand->siglock); | |
2563 | old = current->blocked.sig[0]; | |
2564 | ||
2565 | siginitset(¤t->blocked, newmask & ~(sigmask(SIGKILL)| | |
2566 | sigmask(SIGSTOP))); | |
2567 | recalc_sigpending(); | |
2568 | spin_unlock_irq(¤t->sighand->siglock); | |
2569 | ||
2570 | return old; | |
2571 | } | |
2572 | #endif /* __ARCH_WANT_SGETMASK */ | |
2573 | ||
2574 | #ifdef __ARCH_WANT_SYS_SIGNAL | |
2575 | /* | |
2576 | * For backwards compatibility. Functionality superseded by sigaction. | |
2577 | */ | |
2578 | asmlinkage unsigned long | |
2579 | sys_signal(int sig, __sighandler_t handler) | |
2580 | { | |
2581 | struct k_sigaction new_sa, old_sa; | |
2582 | int ret; | |
2583 | ||
2584 | new_sa.sa.sa_handler = handler; | |
2585 | new_sa.sa.sa_flags = SA_ONESHOT | SA_NOMASK; | |
c70d3d70 | 2586 | sigemptyset(&new_sa.sa.sa_mask); |
1da177e4 LT |
2587 | |
2588 | ret = do_sigaction(sig, &new_sa, &old_sa); | |
2589 | ||
2590 | return ret ? ret : (unsigned long)old_sa.sa.sa_handler; | |
2591 | } | |
2592 | #endif /* __ARCH_WANT_SYS_SIGNAL */ | |
2593 | ||
2594 | #ifdef __ARCH_WANT_SYS_PAUSE | |
2595 | ||
2596 | asmlinkage long | |
2597 | sys_pause(void) | |
2598 | { | |
2599 | current->state = TASK_INTERRUPTIBLE; | |
2600 | schedule(); | |
2601 | return -ERESTARTNOHAND; | |
2602 | } | |
2603 | ||
2604 | #endif | |
2605 | ||
150256d8 DW |
2606 | #ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND |
2607 | asmlinkage long sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize) | |
2608 | { | |
2609 | sigset_t newset; | |
2610 | ||
2611 | /* XXX: Don't preclude handling different sized sigset_t's. */ | |
2612 | if (sigsetsize != sizeof(sigset_t)) | |
2613 | return -EINVAL; | |
2614 | ||
2615 | if (copy_from_user(&newset, unewset, sizeof(newset))) | |
2616 | return -EFAULT; | |
2617 | sigdelsetmask(&newset, sigmask(SIGKILL)|sigmask(SIGSTOP)); | |
2618 | ||
2619 | spin_lock_irq(¤t->sighand->siglock); | |
2620 | current->saved_sigmask = current->blocked; | |
2621 | current->blocked = newset; | |
2622 | recalc_sigpending(); | |
2623 | spin_unlock_irq(¤t->sighand->siglock); | |
2624 | ||
2625 | current->state = TASK_INTERRUPTIBLE; | |
2626 | schedule(); | |
2627 | set_thread_flag(TIF_RESTORE_SIGMASK); | |
2628 | return -ERESTARTNOHAND; | |
2629 | } | |
2630 | #endif /* __ARCH_WANT_SYS_RT_SIGSUSPEND */ | |
2631 | ||
f269fdd1 DH |
2632 | __attribute__((weak)) const char *arch_vma_name(struct vm_area_struct *vma) |
2633 | { | |
2634 | return NULL; | |
2635 | } | |
2636 | ||
1da177e4 LT |
2637 | void __init signals_init(void) |
2638 | { | |
0a31bd5f | 2639 | sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC); |
1da177e4 | 2640 | } |